Without breaking it.
Paladin: Now has taunt.
Mages: Now have a functional 3rd spec option in a reworked Arcane tree. Please pick Arcane and stop freezing me 
Of course, this would be in Classic+ only. We aren’t likely to ever see any changes like this in Classic.
I’ll take bug removal first. Classes should work properly.
Then… #nochanges
#NOCHANGES roll a warrior.
We are protectors of the Innocent, defenders of the Light, keepers of Justice. We would never stoop to a lowly warriors level and throw insults at our opponents. We’re just better than that.
All classes are fine the way they are.
If I could make a change to any class, I’d honestly just give back crusaders strike to ret pallys since it was removed in the beta.
Mages no longer have blizzard. Arcane explosion nerfed. And suddenly classic is a better game. I can only dream.