I'm not a good PvP'er, but I would imagine it could screw the balance in PvP if every class had an interrupts with a short CD. But then again, this issues I'm describing has been here since God knows how long. If you give a class an ability in PvE it usually also has to work in PvP as well. Same thing with items. An example is theVial of Shadows trinket in Cataclysm which was changed because it performed too well in PvP despite being a PvE item.