Would you believe this is the first I've heard of it? True, we're just using the stock forum style that comes with phpbb forum (arguably the most popular and feature-heavy php-based forum there is) , but I don't know if I'm ready to believe that people are giving our forums the cold shoulder because of aesthetic concerns. I can tell you that there are plenty of forums out there that have far worse visuals and only a small subset of the functionality we do, yet still see heavy use (ever been to 4chan?).
I don't know why people don't use our forums. If I had to venture a guess, I'd wager that at this point our user base consists mostly of people that have learned about shmax.com from the signatures in use on other Transformer forums (I believe that's how 95% of our current user base--including Engledogg--learned of us). These people already have a favorite forum. The time will come when we're ready for a larger--and more diverse--user base, but for now I don't really make a lot of noise encouraging new visitors outside of the locals, because the site still needs more work, more shoring up. I still consider the site to be in beta, and the 1600 or so users we now have to be testers.
As you know, I've always got 3 or 4 major projects in progress. I've been quiet lately because I'm knee-deep in one of them now (a complete rewrite of all of the javascript code in use on shmax.com, which is preparatory work for the photo-tagging feature also in progress). After that, I intend to finish the variant system I started, then it's back to the long-promised new appraisal system, and this is all on the road to finishing "shmax 2.0", which will give us a more robust "group" system for parts, and the even-longer-promised gestalt system. And all of these huge projects are themselves only the underpinnings of a greater mega-project that has been in the works for nearly 5 years, which is the expansion of shmax.com to encompass other toy lines.
Meanwhile, I've got people telling me I need to get involved in Facebook, Twitter, mobile, and everything else. I fully realize that these things would expand our user base (and probably light up our forums), but again, we're not ready for it (our poor server can't handle it, and the site is losing money as-is). At the same time, I am interested in the idea of letting users sign in with any of these accounts (see flickr.com). And when I start thinking about that, I start thinking about overhauling things like our member management systems, and I think about how shaky our current "news" content management is (for the moment I hack into forum subsystems), and I start fantasizing about just tossing out the forums altogether and building something up from scratch.
But I'm only one nerd (well, let's not forget Spaceharfang), and all this stuff takes time. So I'll tell you what I'll do. Once I finish my current project, I'll put all the other huge stuff on hold for a bit, and if nothing else, I'll upgrade to the newest version of phpbb forums (which I've been meaning to do anyway, in the hope of fixing some of the log-in issues people report). In the meantime, you and Ed can shop around for a skin you like, and we can try it out. To be clear, you'll have to pick one designed specifically to work with phpbbforum3. The other ones you mentioned aren't compatible. If you're adventurous and want to try your hand at developing a new skin from scratch, I can support that as well.