I don't think ignoring users is the right way to go. If any user is troublesome enough to be ignored by a large number of people, then they're troublesome enough for a ban.
Speaking of bans, banning from certain boards wouldn't be useful for basically the same reasons as above; if they're THAT troublesome, they should be completely banned.
Also, the signature/avatar idea is really a matter of bandwidth and expense. I don't run any site, but I know that signatures eat up a lot of bandwidth, which increases considerably with more users coming in to the site. Basically, the more perks you want, the more it will cost to run the site.
The editing feature is something that all forums need. However, with the edit feature there would be no need to delete your own posts. User enabled locking wouldn't be too bad, but this doesn't seem to be one of those forums that actually need such a feature.
Oh dear... all this commenting on other suggestions has made me forget my own -.- I'll post later if I remember it.
By life end:
- Wii- 100 million+
- Xbox360- 35~40 million
- PS3- 30 million
- PSP- 30~32 million ------------- FAILURE
- NDS- 85~90 million (Skeptical) - FAILURE
- NDS- 100 million+ (Optimistic) -- Success!
