First of all, very nice work from Steph3D ! I know the guy from other forums and he's very talented !

Now a few comments or thoughts about the feature request...

- "Bi Offset" for sure ! but for me the user must have the choice to delete or not the original curve.
- Fillet on curve made of multiple segments : excellent option ! Good to see it will be in MoI very soon !
- Illustrator export. Yes !!! But Illustrator import would be great too ! I very often create complex shapes with the pathfinder in Illustrator. Also, this would allow to easily import text !
- Hotkey for last action repeat. If I understand well, not a hotkey that just recalls the last used tool but one that executes the last command again with the same values. Would be great with "make copies" activated to easily duplicate or rotate objects.

To this I would add :
- Reference images (independant in the various viewports)
- Array functions (already mentioned elsewhere) (on curve, circular, rectangular...)
- Project curve on surface
- Snap options on surfaces or polysurfaces
- Distortion tools (Twist, Bend, Shear)
... (to be continued) ;-)

Err... Forgot Spiral and Helix tools... ;-)