youre forgetting they have a lot of shortfallings too. For instance, sure, they can pretty much ignore the Advent's superior shielding, but then again Advent can bring a (now even more so with 1.1) a ridiculous amount of strike craft to the battle. They really arent a race built to be on the defensive, unlike the TEC. Phase missiles seem to make up for their less-than-flashy strike craft technology.
I mean I could almost make the same argument about the illuminator as you can the assailant. powerful beam weaponry, it can fire up to 3 at a time (Prow, Port, Starboard) and its illussion ability and mighty long range makes it difficult for you to even get a shot off against one. But no, I dont find either Overpowered.