I think the BB developers might need to study whether the game engine is balanced in extreme situations, such as when a team is heavily focused on defense or offense.
This is especially true for zone defenses.
For example, when using two inside players who are specialized in defense, the actual defensive improvement (not just the rating) might be different depending on whether it's a 3-2, 1-3-1, a zone defense with ratings similar to man-to-man (if such exists), or a 2-3 zone.
I suggest starting by checking situations with low shot blocking.
See whether the offensive drop caused by inside defense specialization is about the same as the defensive gain it brings.
Otherwise, even after adjusting shot blocking, it might still be powerful to use a 3-2 zone with two defensive-specialist big men who have extremely high inside defense but low shot blocking—meaning the problem isn't really solved.