I would have to agree that they wardogs should not be able to respawn as they do currently. However, I, like some others here, would not say that they are overpowered.
True, they can rip some enemies apart as their attack is excellent. But, if you face an enemy, especially an armored one, head on, the dogs won't fare so great. Also, the fact they you can't control them after the inital charge definately works against their effectiveness.