1) Cold Harbor Ballista - No red circle whenever it's about to land, it's abused by many (mostly vet pvp / not so much non-vet pvp)
2) Expert. freaking. Hunter - This skill makes me want to repeatedly hit myself with a hammer. In vet pvp, whenever you see that beautiful and glamorous red mark on you, you know you're going to die instantly. In non-vet pvp, only a few know about it but the ones who do usually take out lots of people.
Seriously, patch these things in the next update. I don't want to wait 3-6 months, having more and more people learn about this and abuse it.