I agree, but the range had to be pretty limited; just to use creep range could be overpowering, however, nothing prevents you from escaping, evolving into a lets say tyrant, and then come back.
I am not sure if I should F1 or F2 this, for in my opinion, with some tactical thinking – move out, evolve, come back – this is not really an issue, but on the other hand, I agree that the current situation pretty much hands the alien base over to the humans on a silver tablet once they manage to get somebody into the alien base, so I would limit this “overmind-power-range” pretty much, but allow aliens to evolve into anything within that range even if an enemy is nearby.