you know what, all these different BBS suggestions have been made, but I doubt anyone has mentioned what I'm about to say (sorry if it has been . . . it isn't exactly easy to wade through 27 pages of posts, heh).
the forum coding should be changed to phpBB, or something similar of the sort. almost ALL forums these days are using phpBB or something similar, and it is by far the most efficient and effective forum system around. I'm sure some expert NG coders could take phpBB and modify it accordingly for Newgrounds' needs (phpBB is open source).
phpBB contains almost all the features that have been suggested (editing posts, private messaging, etc.) and is very easy to implement and maintain. I'm not some advertiser for phpBB or something, but I have had experience in the past with starting, operating, maintaining, moderating forums and I've found that almost everyone uses phpBB for the reasons listed above.
it just seems that the NG BBS is in a completely solid-state, with upgrades and revamps being very tedious and difficult to implement. be that as it may, this is just my opinion. I am in no way some expert on the topic, and I don't really speak with any authority except by my own experience. I know NG BBS is already running on a php forum system, but in my opinion, switching to something more widely-used and something more flexible would be best . . .
hope that helps in any way/shape/form. cheers!
**Footnote** I'm pretty sure everyone knows what phpBB is, but in case: phpBB