Maybe I am confused? We know the rebels have raid where they can bring any force into your planet, no warning. What is to prevent a person from camping rebel heroes over a planet and bringing them in once the raid starts?
My general view on the balance issue is Petro spent alot of time figuring this thing out. I am more likely to feel their take on balance is better than ppl that have been playing as Imps or Rebs for years and are indeed bias.
There seems to be a call to have the ZC be the weakest little sisters of the poor and be last in terms of power. I just don't agree with that and apparently neither did Petro.
Finally, the one thing I realize is that it is almost impossible for a RTS to have "perfect" balance in terms of single player vs multiplayer. There are just some things you cannot predict that humans will do, because humans will do "ANYTHING" to win.
I will say the balance for playing single player vs the AI is great. I am old school, from the days "before" multiplayer and still prefer that brand of play over playing the I'll do "ANYTHING" to win humans. I understand that is a minority view, but that's me and maybe that why I'm having so much fun.
In the end, maybe the answer is different rules and setup for multiplay, because that is where any inbalance becomes a problem due to the way humans exploit things to win IMHO.
Only the blind can see.