Rocketjumping and trickjumping are what turned me off Quake 3 and, eventually, Enemy Territory, so I'm not too enthusiastic about increasing the role of gimmicky jumping tricks in JJ2. Even though it'd be easier to do them with a dedicated button, it'd probably mean skilled players will rely on them even more, and since control over your movement is still a large part of RF jumping skill, that would thus only increase the learning curve, potentially turning off newer players.

But I'm not exactly one who plays JJ2 competitively a lot, of course.