I think it should be good.

I think wand damage should be relatively low so you probably don't want to use it as your main attack, except for early lvls maybe. But you can make water with mage and convert hp to mana on warlock.

The only sort of negative thing is that I think paladin will probably mostly just idle when there isn't anything to heal or use supportive skills on, but it will be a great support when needed.

Paladin have Divine Shield, Blessing of Protection, Blessing of Freedom. Auras. Hammer of Justice. Lay on Hands. Really supportive skills.

Mage have Frost nova and since you will be Alliance there won't be any gnomes that escapes from it. Great to buy some time against melee. With Ice block you have another way the opponent can't kill you quickly.

Warlock can get Soul Link from spec (not neccesary the best but a good option if warlock gets nuked much) to get 30% of damage taken shared with pet, and with voidwalker you can sacrifice it for a strong shield. So warlock should be hard to kill also.
With felhunter you can dispel, so you have 2 characters that can dispel magic effects so you should be able to counter CC quite well.

Healers shouldn't have any chance of surviving your Counterspell + felhunter silence + Hammer of Justice.

I think you should easily be able to use mouseover polymorph or fear, using both without focus would be hard, although you could control mage and use mouseover polymorph and fear on your target.