> Would it maybe make sense to make a separate thread creation page?

Considering that the ratio of users who start new threads to those who don't is pretty small on most message boards, I think it does.
A seperate page could also be used to put a more visible disclaimer/set of rules, as a seperate page with a different layout is likely to generate more attention from the user. Stuff that can be put there also wouldn't clutter up the frontpage.
I don't think this is an urgent matter, though.