Hi Martin, for the v3 wishlist post your top 5 wishes on this thread here:
http://moi3d.com/forum/index.php?webtag=MOI&msg=3628.1

Then for the Blend, like Pilou mentions you probably want to boolean together those 2 pieces so that they are one object and then you can select edges that are sharp and use Construct > Fillet to round them off.

It looks like you may have cut the handle using the Trim command instead of using booleans? Trim is a surface modeling operation that just cuts surfaces up, while the boolean commands are focused on working on volumes.

So in a case like you had there where you've got 2 solids that you want to combine, use boolean union to do that rather than Trim - they both basically do the same general job of cutting things up, but using Trim is a more "low level" type operation where you will need to manually pick which fragments of the object to discard and then later on use Join to glue the pieces together.

Booleans are sort of like a high level batch mode version of trim that automatically decide which pieces to discard depending on which volume they are contained in and then also automatically join the pieces together, so when you have solids it wraps up a few different steps and tends to be quicker than using Trim. Trim is more to be used for when you are modeling individual surface pieces rather than solids.

You were also asking about Blend - blend is also a kind of lower-level surface modeling operation that will make a new surface that connects between 2 edges of other existing surfaces. It's meant to be used when there is an actual gap of empty space between the pieces you are blending, and then Blend fills in a surface in that empty area. When you have solids that have sharp edges that are touching each other at shared edges where there is no gap between them then you use Fillet for rounding off things like that instead of Blend.

See here for some examples of Blend - notice there how the pieces that are being blended there are apart from one another with empty space between them, and then Blend creates a new surface between them:
http://moi3d.com/2.0/docs/moi_command_reference7.htm#blend


Fillet is in a certain sense a kind of batch mode of doing Trim + blending + joining on solids, because filleting incorporates cutting away some of the material of the edges and then putting in a rounded piece between them.

So if you're working with solids, try to use more of the solid modeling part of the toolset like booleans and filleting rather than trim and blend, and that will help things go faster since it bundles up several steps for you.

Hope this helps, let me know if this does not make sense.

- Michael