Have "Roots" and "Stalks"
Some of this might not be necessary when the upgrade trees for both sides are finished, but stay with me.
Nothing is worse as gorge than having your pretty hydra garden rocked by some random nades. (Its not much more fun when its an ARC, but that's what an ARC does.). It makes it hard to build up a viable defense, especially at 10 pres a pop. At the same time, if hydras were too robust, they end up being over powered; there still needs to be a way for marines to break through a hydra-secured area.
So, how can hydras be made a better pres investment, while still allowing marines to push through a defended area?
I'm proposing the Hydra be separated into two parts: a "Root" and "Stalks". The stalks shoot the projectiles, and the roots spawn the stalks.
The stalks would be like the hydras are now, anything kills them.
The root would only be vulnerable to ARC, Flamethrowers, Axes, and lack of infestation. (Or at least heavily resistant to any damage that isn't from those sources.)
So, I'm a gorge, and my gorgefort is getting nade spammed. When those grenades explode, they take out the stalks of my hydras, rendering them unable to fire. If the marines are actually pushing, they'll be able to walk through the area safely, since the hydra's offensive abilities are disabled. If the marines want to hold the area, taking out the cysts will cause the roots to die fairly quickly. Flamers and ARCs could also be used to take them out and drive me from the area. And in early game, the roots could just be axed.
But, if the marines are just lobbing grenades/bullets into an area, once the damage stops, the still-existing "roots" will begin to grow new stalks. This would make a failed/halted marine push much less costly for the aliens.
The idea would be to reward the marines for securing an area, or at least pushing back the infestation long enough for structures to die, while reducing the effectiveness of failed attacks.
What do people think?