I really don't know how this could possibly effect the gameplay
So, very often I see that a game gets stuck because of whip spamming or turret spamming, etc.
Maybe this could be solved by having infestation or power-nodes getting "weaker" the more structures are build that are supported by the cyst or power-node in question.
Possibly differnet kind of structures would weaken the cyst/power-node by a certain percentage. This way an area with a lot of turrets could more easily be taken out by just destroying the power-node. Now a lot of aliens could kamikaze-destory the power-node.