When I first came out with my capabilities, there was some discussion around the civs being "overpowered" partially because of them, and presumably because of the powers revealed by the early lynches of civ specials.
As mafia have died and their powers revealed, that doesn't look to be the case. As JTP noted, without my civ powers, the balance might be the other way.
There are most probably mafia roleblockers still out there.
My investigation of Rommy was the night after he claimed that he had stopped ALL the night actions the previous night. I knew the action stop was true because I had an action that was stopped. All night actions had been stopped. If Rommy was civ, and could do that, I certainly wasn't vigging him, because it might be repeatable, and it might be useful again. However, the claim was all Rommy poetry.
What we still don't know is who was able to stop ALL actions that night. Was that done by a powerful civ, powerful mafia, or ???