Very solid post for sure, but a factor you haven't addressed is the luck issue. In my opinion, jumping and kicking both require skill, and even though I feel strongly that kicking requires more, that's not the matter for immediate consideration.
The issue I'm taking note of is that good kickers, on average, have far more control than good jumpers of where the object ball will end up on the many shots played out of a snooker in which no attempt is made to pocket a ball. Object ball speed is something very few who jump can control with any precision, even at the most elite pro level based on my observation.
Hence, for the many jumps in which no attempt is made to make a ball, an extra luck factor is introduced in nine ball because so many of those shots are of the "make a good hit and pray for a good result" variety. For all but "A" players and above, this extra luck factor is enormous, but even for the best jumpers in the world, it's true. The jump cue has dumbed the game down AND added a luck factor better dispensed with.
All that said, my view on the jump cue hasn't changed in over a decade. I feel that use of the jump cue should be restricted to the very first shot of an inning. In other words, if opponent hooks you, then you can use the jump cue, but if you hook yourself you cannot. One should pay the full price for position poorly played.