Li Shenron said:
Not to mention that a DM could rule that if the tripping AoO is successful, the "tripper" may get a second attack because of the other benefit of Improved Trip.
My point exactly -- except that this isn't a judgement call on the DM's part. Rather, this is what the rules would unambiguously call for. The combat would look like this:
Opponent with combat reflexes, improved trip, and a reach weapon: I delay.
Poor Player: I charge that mofo!
Opponent: Ooh, an Attack of Opportunity, eh? I trip him. W00t! He's down! I use my extra attack to whale on him!
Poor Player: Crap, that ends my turn, right?
Opponent: I stop delaying. I whale on him! I whale on him!
Poor Player: My turn again? Fine, I stand up, step forward 5' --
Opponent: Not so fast! You stand up? I take an AoO to trip you. W00t! You're down! I use my extra attack to whale on you!
Poor player: Crap! Fine, I use my remaining action to try to stand up again, and then I'll move back 5' --
Opponent: Not so fast! You stand up? I take another AoO to trip you again. W00t! You're down! I use my extra attack to whale on you!
Poor player: Crap, that ends my turn, right?
You see the problem. Under the old rules, at least the poor player could have stood up, moved forward 5', and gotten a single attack off on the Opponent without fearing an AoO; as it is now, if the tripper's got enough of a tripping advantage, the poor player can never close in.
Daniel