OK, enough has already been said about Repulse being an overpowered ability. I'm not going to rehash the whole argument about how a couple Guardians can effectively hold off a fleet of HC's. I want to focus on one small aspect of Repulse.
After yet another game where some enterprising Advent player pushed a couple of my capitals around for a few minutes until they managed to kill them, the really irritating thing that I noticed was that a ship loses all its momentum when it gets pushed. This isn't a big deal for small faster ships, but capitals move so slowly that a loss of forward momentum is a death sentence to them.
Each time a capital gets hit by Repulse, even if it is a tiny bump, it stops moving. Soon it gets swarmed by whatever ships were chasing it, some getting in its flight path, making it even harder for it to accelerate out of there. This also hurts a cap trying to execute a turn, because they never build up speed while in the turn, so each little repulse bump is effectively preventing them from turning around.
No other support cruiser can kill a cap like this. I have always been on the fence before about Guardians affecting caps because I also never liked the idea of a fleet being pushed away and leaving the capital by itself. I've finally decided that Guardians should not affect a cap, or if they do, they should not interfere with momentum so ships being pushed can continue on their way once the repulse effect repositions them.