I agree that the "I quit" and the "WoW sucks for all of these (illegitimate) reasons" and the "RIFT IS THE BESTEST GAME EVAR!!!1!!11!111!!1one!" threads have gotten quite old, mostly because they usually never contain anything constructive, but (unfortunately) I doubt they'll ever start banning them instantly. Luckily, they usually turn into flame-wars and troll-fests so the mods lock them anyway.
However, if the posts are constructive and if they offer good feedback and harbor civil discussion, then I'm all for them, but they almost never do.