Make the Overseer corruption ability 50 energy. Perfect for stalling an upgrade or two for 2 minutes or so….
Now those roaches are 2/2 to the slowed enemies army to only 1/1 upgrades
Or hell revamp the entire ability to if the unit produces during corruption it becomes a zerg unit as it emerges. Kinda like spawn broodling but you can always find and cancel production which would serve the same purpose as making the building useless.