To incorporate height into the Game Engine would require a massive overhaul
dont think so... it could be done simply by multiplying for a coefficient the rebounding ability before the simulation, just to take the example you did
That is indeed rather simple, because all you essentially change are the inputs going to the game engine. But that's a totally different thing as the height mismatch concept proposed. To consider individual height mismatches, every applicable comparison in the game engine would need to be modified to take the height difference of individual player pairs into account. That would require major work. It's not necessarily as bad as it sounds (we do not know the exact implementation after all), but it can be pretty bad.
Currently, height plays a role in the training and a tall player with respectable rebounding arrives at this level for different reasons than a shorter player, as Juice explained. In practice only very tall players will reach the highest levels in skills that train slower for short players and vice versa. This makes sense. Multiplying the inputs to the game engine would simply alter this logic. Would that be better or worse? I think it could certainly be more intuitive for new users who haven't read and understood the rules yet. Overall, it would however make player comparisons more difficult and would not really add anything to game play. It's not an option worth considering at this point in my opinion. It probably was something the BBs considered in the very beginning and then decided that the current system makes more sense.
The height mismatch proposal pops up every now and then. I'm undecided about it myself. It would certainly introduce more variation to game play, but that's not necessarily a positive thing. Anyway, it would require a lot of work and is not something that is even considered as far as I know. The current height system is actually pretty nice. It's sophisticated enough and it's very simple.