Just have to point out that removing the ability to assist quantum gateways is an extremely stupid idea. Flux economy and controlling the amount of buildpower you use on something is the bedrock mechanic which the entire game is built on. Excluding launchers, which have some weird behavior when mass stalling that I think is stupid, everything obeys the elegant and simple rules of mass, energy, and buildtime. You cannot just say that this one type of factory is impossible to assist because you don't like the units it produces or because of quantum magic, it would be an unforgivable sin going against the main design principle of the game.
If you want assistance to have less of an impact on quantum gateways you just increase the buildpower of the gateway and increase the buildtime of the SCU so that the external buildpower has less of an effect. Exactly the same thing that was already done with nuke launchers.