"Anyway, Wilson doesn't work for the CIA, so he can't really leak security secrets, but his wife can."
You actually have this backwards. Under the law, Plame could not be prosecuted for "outing" herself (if she was covert, which she wasn't).
But Wilson could be.
It wasn't Plame's identity that is the main issue. She wasn't covert, anyway. I think that it is other classified information that was making it's way out of the CIA that is the concern of this investigation.