I mean, while I am opposed to the idea of shoving RP off in it's own little corner, I'm there are still people who would want one on one engagements (take that as you will). Maybe a sort of PM system could be put in place? Not only would it provide something for the roleplayers (if they truly wanted it), but it could also be used for those who'd just like to chit chat with one another, and not flood a thread.
I dunno. It's just a thought, and probably a dumb one at that.