Time for my $0.02.
From reading so far, it seems like a given that the current archive of threads/images/etc. will be migrated to the new system, or at least preserved in a read-only capacity. That's the most important part of the transition, I think, so as long as that happens I'll be happy as a clam.
I do visit the site with IBrowse, but not exclusively, so I wouldn't be "locked out" with any CSS additions. That being said, it would be nice for the site to "function" (I.E., read and write posts) with IBrowse, even if it doesn't look good. Sometimes it's quicker to deal with IBrowse's limitations than to boot up another machine.
Regarding improvements, I would *love* to see a bounties module for OS3.x projects. I suspect that the majority of Amiga users still don't use OS4, MorphOS, or AROS, so for everyone still on classics and WinUAE (the easiest way to get into the platform), bounties might be a good way to extend the life of the classics. For me, pushing the machines farther than they were ever expected to go is part of the fun of the Amiga. It would also reaffirm community support for developers.
I'm also evaluating CMSes at the moment (albeit for a much, much smaller [non-Amiga] project), so I appreciate the challenges you're facing, Wayne. Thanks for the opportunity to chime in, and I'm looking forward to the end result.
