first, i agree about your point with SolidWorks getting over complicated. i hate that program with a passion. i'm a trained mechanical draftsmen and you know software is crap when it's quicker and easier to just grab a pencil and do it on paper. i really enjoy MOI's simple and clean interface. i only discovered MOI a couple days ago by pure accident and having played with the demo, i find it to be a pleasant mix of something between Rhino3D's technical capabilities and Sketchup's simplicity.

which brings me to an idea that someone near the top posted about two editions of MOI. i would actually encourage this idea. take Sketchup as the example of success. their free version is probably about 75% complete compared to their paid PRO version. this tactic gets Sketchup into the hands of everyone and after a while it becomes their friend. i'm a member of a hobbyist group that does wargame terrain modeling (www.hirstarts.com) and Sketchup is heavily used in the community for design and layout of buildings brick-by-brick, because it's free. the caveat is that the free version is for personal, educational, and hobbyist use and if you use Sketchup for business you are supposed to upgrade to PRO. the attraction to the PRO version is that it's ability is expanded past it's proprietary file import/export and there is a slew of extra tools that would unlikely ever be used for personal reasons. this is where upgrading to PRO makes sense for business use, not to mention the extended tech support.

if you were to make a "free" entry level version, i would suggest disabling things like scripts, some of the more complex tools, and probably import/export outside of the .3DM format (unless you come up with your own proprietary file format or header for .MOI) in order to make the full version more appealing. the gimped free version gets it into their hands without any pressure and when/if they're ready for more complex things they will upgrade without hesitation, because they are already comfortable with the software. otherwise they will happily recommend it to others who are looking because they've developed goodwill from the experience. it's just a thought to increase your user base.