Assuming this is for classic? If so, tanking is not as much of a requirement as it is on live. You can overpower a lot of content without a tank which is why the 4x mage / priest works, you can CC / Heal and just burn down the npc.
So warlocks would also probably work if that's the class you enjoy playing.

On retail you typically need some type of tank due to mobs living longer/special mechanics. With that in mind, you can still do 5x of any class and probably clear a mythic 0 without too much trouble. When you start ramping it up on mythic+, it cuts down on your options.