What do you think of giving the network mechanoids a chance of resisting an ai takeover? At least the fully upgraded one.
Rather than relying on upgrades, may i suggest the same thing except use base chance on thoughtdefs? For example, a recently charged, undergone recent maintenance, bonded mecha would have less of a chance of going maverick than a low power, damaged, overworked (overheating?) mecha? Similar to how pawns have higher chances to have mental breaks the lower their mood is.
+1 to anyone who gets the maverick reference

Edit: Except of course the mecha would always have a chance to go berserk, thus always leaving the player wondering when the inevitable will happen