Well, no one stops you from building a 5000 ton FAC, only that it's probably a very slow attack craft by then.
Scalability would probably address this better, or an auto-scaling system that decreases the effect based on ship size.
Ultimately, in the long run, shouldn't Electronic Warfare be revamped anyways?
It's not much Warfare right now. It's another form of cloak.
I'd like some offensive potential.^^