It's been proven before that for several reasons bases cannot be balanced gameplay-wise. Ship to base combat is imbalanced either favoring the assaulting side or - at the current state - the defending side.
Just god damn make them SRP only with lighter requirements than the current ones. Make assaults an inRP feature, like events, scheduled beforehand, and bases balanced that way to be destroyable during such an event. And of course regulate anything connected to bases via rules (something I've been missing for quite long). These things would ensure that bases will indeed be inRP objects, and not something to reward ooRP grinding and powertrading.