This a fabulous idea, especially given the ongoing controversy about SC's with life drain.
The complete lack of defense after the early game is an enormous issue for me. Even "good" PD (Jotun Marignon etc) isn't cost effective.
The castling strat is a direct response to the futility of defense.
This would go a long way torward making the game more perilous for the SC weenieness that dominates MP.
Let's Overdo it, and then scale back to balanced?

I dont trust the SC-mongers to stay cowed.
PD would need to be scriptable to make this truly formidable though. (Good idea anyway)
Yeah, Panther!
Rabe