So I noticed today when logging on for prepatch that Frozen Orb is for frost spec only. When in original MoP all specs had frozen orb up until WoD prepatch (according to wowhead, i also remember using it myself in MoP) when it was changed to be frost only. I believe this is a bug because I cant find any notes of them keeping the WoD change for MoP classic and because as far as im aware none of the class changes theyre doing is supposed to effect pvp, and obviously losing a decent 1 min CD is a pretty big effect to pvp, at least for arcane mages.