Beat it with this undead paladin horseshit. The only thing more idiotic is gnome druids. Undead priests using holy magic is already a gameplay concession than CDev gave some stupid handwavey excuse for back during Cata, and if it weren't, it's completely perpendicular to their theme anyway.
Night Elves are pretty much confirmed at this point, and it makes sense considering the unification of the Light and the close relationship between Elune and the Naaru that Blizzard has pulled. If they need a counterpart on the Horde, the only sensible answer is Trolls. It's a great opportunity to reintroduce the Zandalari in some fashion, too, especially if they're going into the Azshara/N'zoth stuff next. Shame they look like shit in plate.