The best feature for a surface modeler is the possibility to create n-sided surfaces and choise the type of continuity on each border, like this: http://www.rhinoreverse.icapp.ch/english/video-tutorial/tutorial.html (NURBS Functions->Patch Surface Holes) but with the control (positional, tangency, curvature) like GSM of Thinkdesign: http://www.youtube.com/watch?v=OJ2jwglci70&feature=related With these feature you can do all shapes!
- Save and Load Polygon Mesher settings. Offer Named Pre-sets (i.e. Low Polygon, Accurate Curves, Output to E.I.)
- Option "Maximum distance to surface" for creating meshes (at least STL meshes) (Maybe call this "Max chord height", or "Deviation tolerance")
- Untrim for a particular edge(s) of the trimmed surface
- Multiple Undo!
- Automatic rebuild/simplify type option to reduce complexity of offset, project and intersect (surfaces) commands
Snap to a surfaceDone!
- Separate undo/redo stack for "viewport changes" like in Rhino (Home/End)
- Enable to mouse right click on a small tag to pop up a cline menu
- Sweep improvements, see forum post
- Make elliptical arcs smoothly deformable, see forum post
- Merge Revolve and Rail revolve into one command
- SelVisible method could work with control pts / point objects (low priority)
- rebuild curve (really, this is missing)
- rebuild surface, with editable U/V isolines (I know, not for 1.0 :)
- stronger fillets operations : for example a fillet with a too high value should produce automatically the biggest fillet possible, it should not fail.
- multi-threaded operations if possible
- extract U/V isolines
- unified mapping coordinates if possible !
- support incremental import/progress bar/partial import for huge .igs imports
- Multithreaded import/meshing
- Driving Dimensions, capture design intent at any product development stage.
- 2D Design environment, Associative Drawing environment to enable design changes, as well as geometry creation and modification, from within drawing views.
- 3D Annotation capabilities and highlighting tools to clearly communicate and document design changes.
- Design Tree, A single design environment for working on an assembly and its individual components, parts can be easily merged together or split to individuals piece parts as the design evolves, hierarchy can be changed by Dragging & Dropping component designations around in the Design Tree.
- And last but not least a script or export wizard for maxwellrender?
- Suggestion, publish your project to the PDF format, whether you want to print, or further edit the layout of an illustration program.
- Variable radius fillet, with being able to define radius by a profile/scaling type rail.
- Bending an object along a curve (and some "transformers")
- A pipe maker
- An "explode" function after a "boolean merging operation" for have each object on a 3D grid (that is impossible to make that by hand when objects are more than 10 ;)
- Something for manage object (color (?), group(?), arborescence (?)...)
- Something for manage "curves generator" (hide /show) (rank) (?)...
- Complete history rebuilding
- Save "Helpers" in a file
- Automatic selection of a close curve existing
- Colored curves
- Record actions for replay and see the creation
- Vocal commands on each functions
- Divide function for put points along a curve
- Colors on forum choosen by user (title or more ?)
- a random function for some effects
- level of transparency for object on the screen for easy modification
Format FBX for 3DSMax & MayaDone
- Format Collada
- Add a rotation on the Scale Array & Array curve
- Free Hand : snap to objects
- Circle (ellipse) selection (like the rectangle selection)
- Exotic grids :Spheric, Hyperbolic, logarithmic....
- A Function Blend "straight angle"
- Select a 1 / 2 points of a selection (or any 1/ n ) see forum post
- Group, Objects, Types, Styles...expanded in their last states in a new restart
- Elliptical fillets, where you specify two radiuses for each side of the fillets.
- Option for reducing the number of points generated in an offset surface at the expense of precision.
- Option to apply distance constraint immediately like AutoCAD style direct distance entry forum post.
- Better UI for filleting edges - some kind of UI that lets you click and drag a cross-section of the fillet to adjust the size.
- Method for cycling between different objects under the mouse forum post.
- Method for "Zoom previous" to step backwards through previous view states.
- Simple Dimensioning objects
- 2d Flattening tool with hidden lines having it's own style or color
- AI export that keeps the color information of objects
- Instances to help speed up large files
- Option for extending curves interactive with the mouse forum post
- Quick trim command, cut clicked on object at the click point rather than selecting objects / Trim / Add trim points forum post
- Variable radius fillet
- Text along a path (along a curve).
When using the Array > Dir command, an extra option to choose the placement for the last arrayed object, not the offset point as this is currently the case.Done!
- Constant width fillet (see forum post)
- N-side surface patch
- point control on surface and also add a point to the surface
- input material properties, if not just input density to calculate weight of a part / assy
- Generate BOM
- Automatic dimension on 2D drawing
- Selection tools : Select chain, select tangency, tangent propagation, etc.
- Always agree if MoI can import 2D DWG file
- Interference detection between object / part
- Zebra strips
- Curvature comb / check
- Properties panel that lets you see and change properties of the selected object, like edit the radius of a circle that is selected, or the length of a line. See video posted on forum.
- Option to limit depth of curve projection
- Surface edit command to pull surface through a given curve (see forum post).
- From forum post (with video) :
- 1 add remove points from surface (isocurve)
- 2 change surface UV degree with preset like , soft U2 V2 ,normal U3 V3,hard U4 V4 surface .
soft surface is good for sharp edges in single surface
- 3 change nember off UV and degree on creation off , cylinder ,sphere ,box ,toro
- 4 color , reflextion ,transparency for surface polysurface
- 5 groop ungroup objects
- 6 fix filet and shell
- 7 stitch surfaces
- 8 join or heal trimed surface edges
- Option to keep cutting object in boolean difference forum post
- Some method to scale an image from the center instead of anchored to the corners only.
From Al Greynolds:
STEP file support
- I'd really love a shaded view, without the wireframe.
- i think a good feature would be an expand selection key such as numpad+ so that when 1 or more points is selected hitting + would select the sorrounding points expanding the selection each time. would also be very usefull with curves especially curves with crowded points
- Sketchup (.skp) file format import and export.
- Method to lock x,y,z axes: http://moi3d.com/forum/index.php?webtag=MOI&msg=1343.1
- Template files
- Mirror / Symmetry mode while creating objects
- displacement painting like in silo?
- T-splines plugin (and or mesh converter)
- Shadows (ala sketchup)
- Toon like shader or colours option.
- Image copy to clipboard
- Checkbox option for placing side pane on left side
From Cedric (cebelab):
- More 2D vector output options
- Line widths
- Option to generate hidden line drawing, choose line widths for silhouette, interior, and hidden lines, ability to turn on/off tangent edges.
- Orthographic option for the 3D display
- Scale preserving AI export - 1mm in MoI = 1mm in illustrator
- SVG support
- Example image
- Some way to control the grid to make it display on top of everything instead of below everything.
- Object transparency slider to make it possible to see through objects.
- Enable planar surfaces to be used as profile curves for sweep, so that things like a hollow tube can be swept in one action.
- Write image thumbnail to 3DM files 
- Feet and inches coordinate display and entry, like: 14'5"
- Some visual indication when a calculation such as a fillet failed immediately (See forum thread)
- Some method to export the display mesh to a file.
- Could it be possible to create a mesh within MOI without export? Since exist a copy&paste conection to Rhino, this could be a shortway for the mesh from MOI to Rhino.
- Support multi-core CPUs in meshers.
- Better mesh creation workflow - allow adjustment of settings during meshing and abort and restart the meshing if parameters change.
- Something like this Deformations
- Move the Grid when there are big and numerous objects
- System of objects / groups with different quality of numbers of polygons for only one export!
From Mike Fitz:
- More lighting choices to help avoid really dark/black areas.
- It would be great to be able to see MoI objects you want to import. Not only that, but once MoI will have groups I want to be able to go into that MoI file and pull out just a group or a named part from that file. Just think about it, you can have a file that contains 300 gears, and you only need one of them.
- Sweep valuable on the 3 Axes of the helix (not only z)
Orientation mapping tools for snapping a planar face from one object on to a different planar face: forum post.Done! Added in v2 under Transform > Orient Add some calculator type functions to the numeric pop-up panel, like +,-,*,/, and =.Done. You must use keyboard to write math operator, though. Checkbox for hide/show view controls in Options dialog,Done! Added in v2 under Options > View > Show view controls
- option for position of view controls.
- Thumbnail preview for File open dialog
Some sort of visual confirmation (non-interrupting flash somewhere, message, something like that...) That a Save, Save As, or Incremental Save has finished successfully.Done! In v2 a modified file is now marked by an asterisk * at the end of its file name, and when you save the asterisk is removed.
- Visual confirmation for copy forum post
- A way to preset/save 3d views.
Inscribed / Circumscribed option for Polygon command.Done! Circumscribed checkbox added in v2.
- Notes like Rhino
Option for Array Dir to pick entire distance rather than distance between items.Done!
- Command for arraying on a surface.
- Manual function for merging co-planar surfaces.
- Merge compatible conic-section or extrusion surfaces together similar to co-planar merge.
- While wishing, view clipping objects in 3D viewport with would be nice. Like L- shaped clipping planes, or S-shapes, or even double curved clipping objects (with adjustable thickness colors).
- Developable surface unwrapping
- Curvature analysis tools - min/max curvature, mark inflection points with point objects, see forum post.
- Extend to apparent intersection.
- Freeform extend.
Snap to only visible points when hidden line display is disabled (forum post).Done!
- LWO export - option to export all items as one big disjoint mesh
- LWO export - option to discard materials
- AI export - option to export point objects as little circles
- Optional 2 radius values for cone to be able to make a truncated cone.
- Additional SpaceNavigator modes (see forum post)
- Ability to check volume
- Option to show surface isocurve density rather than set to zero
- When making a line can we have a tick box under repeat for both sides
- Allow lofting to a point (example: )
- Option for 3D view to be parallel projection instead of only perspective.
- Option for surface trimming to project using cplane direction similar to curve trimming.
- Option to return incomplete fillet results when full fillet calculation not working (forum post)
- UV texture coordinate improvements 
Setting for disabling the numeric pop-up panel and just have keyboard input only for that.Available in v2 in moi.ini, under the [UI] section, DisableNumericInputFlyout=y
- Option for Inset command to keep inner plug part separate with groove value > 0. forum post
- Vertex-based filleting for solids and surfaces 
- Add PNG as a file type in Save dialog, to enable saving a screenshot without having to paste into an image processing program.
- Options to keep boolean cutting objects instead of having them deleted (forum post).
- Double-line tool for making architectural floor plans.
Option for view rotation around local frame of reference such as solid modelers (forum post)Done - Rotation style = Free rotation under Options / View / Rotate/Pan/Zoom options.
- Revolve - allow faces as input to revolve and handle capping better for partial revolves (forum post)
From Eric Clough:
- Ability to tear off toolbars and move them to another monitor. (forum post)
- Timed autosave forum post
- Lasso type selection tool
- Command to simplify lines and arcs like Rhino SimplifyCrv forum post
- Method to make the grid show up on top of objects forum post
- Option for which page to import on a multi-page PDF. forum post
- Double-click on a background image name in the list to bring up a properties dialog to allow changing the file path. forum post
- Option for curve export to OBJ format forum post
- Function for randomizing position of objects forum post
- Model repository / library / browser mechanism forum post
- Method for producing a virtual mirror to make it easier to see what the full result will be when modeling only half an object forum post
- Loft with "Guide Curve/ Rails"
- Option to rearrange viewports to European style layout. forum post
- Option for Grid array to have Offset + Extent mode similar to ArrayDir forum post
- Better batch behavior for offsetting curves forum post
- Circular selection area mechanism forum post
From Benjamin Cillo:
- Multi-letter shortcut key combinations forum post
- Method to arrange styles into collapsable folders for organization forum post
- Option with Space Navigator to move forward freely while zooming in a perspective view rather than approaching the rotation pivot point. forum post
From Don Cheke:
- Ability to edit width and height values for existing images, in image properties dialog.