The defenses for this thing seem a bit much to me, it can basically defeat anything that comes near it and thus can't really be destroyed.
The Variable Voltage Hull Defense System, makes it so that a person can't get near it to disable the crew. The active defense system means that missiles and those large projectiles aren't going to get near it, the gravimetric shielding means scaler attacks are useless. The Electrostic Shielding makes energy weapons a no go against it and the scaler shielding pretty much backs up the gravimetric shielding.
All of this makes the tank a fortress of steel that can't really be taken out, even by Mindy power armor or a Tasha Tank. Even the Mindys and the Tasha Tank have weaknesses and aren't impervious to attacks.
I would suggest you to re-examine these defenses and put in some form of a disadvantage to using them. An example would be that they can't operate for long periods of time, or that they can be overwhelmed (it's not mentioned, but because that isn't being mentioned, a GM can metagame this tank and make it seem like nothing can harm it)