Ok, here is the problem with generators :
We start a game, player 1 vs player 2. Player 1 goes offensive, Player 2 goes for a less aggressive, slightly techy build of 2 generators. Player 1 gains the mapcontrol as he spent more money on the army, thus increasing his +Req massively. Player 2 will have less req, but more power.
Now, player 1 spots that the player 2 is teching to vehicles, while player 1 is still in tier 1. Player 1 desperately tries to get the generators up allowing him to get tier 2, but since he did not build a generator in the start, he can´t get generators up fast enough because he lacks power. Player 1 has massive req advantage over player 2, but still can´t get his tech up. Player 2 gets his tanks into the field, starting to take back mapcontrol. Player 1 finally gets enough power to get tier 2 research going, but it is too late.
It is IMPOSSIBLE to turn a req advantage into power, i don´t mind if i have to spend all my requisition to get my power up, at least i would be able to do it fast. If generators scaled ONLY in req, harassing would still hurt, Power would be still scarce.