I'm new here, but I found a few things as well...

No back/left/bottom views. Perhaps clicking on the front/right/top views a second time to get the opposite side?

3D could probably have a corresponding ortho mode, for doing planar stuff that doesn't align with other standard views.

Export of .obj a little messy. Seems that each surface is a separate part which is grouped/combined to create the mesh. This means that in some sections vertices don't match, etc. Is it possible to create an .obj where edges match on joining surfaces and vertices are welded? This also explains why Wings3D has strange stuff happen upon import. Considering the way some objects behave, it's suprising they can import to Wings. (Wings will produce "temporary" edges, which suggests something weird going on with vertice order.) If this can be figured out, the program would work better alongside subdiv modelers. As it is now, it's only seems good for straight to render with no other tweaking.

Not much in the way of simple documentation beyond a descriptor. Not everyone comes from a nurbs background with an understanding of how the tools should behave. Some seem simple enough to figure out such as booleans or lofting, but others such as sweep or blend might need more explanation to newbs. (Having a lot of "whaaa?" moments with sweep until I figured out I was doing it in backwards order. I'm still having surfaces balloon out though. Blend doesn't seem to do anything at all.) Even setting up an "official" wiki somewhere where the well initiated could explain things would be nice.

Future pricing? (No nurbs parallel to Wings3d yet, but Silo maybe...) What is the plan? Is it going to be around $100(US) for absolute beginners? Or is it going to be more expensive and cater to professionals who may be able to throw budget money at stuff for a "simple" pipeline tool?

I do like the interface, so you should stick with it. It's simple for the most part and pretty clean. Nothing is really hidden in the depths of the program or relies excessively on hotkeys. So it's not overly complex or confusing like Blender or some other "professional" programs.