I would do two versions of Demonology: one a tank and one a DPS. The DPS one would have meta and be like it was back in WoD or MoP, I think it was MoP. The tank one would, instead, just have you combine with demons for different things like:
Combine with VW for every spell giving you a shield for 20% of the damage you deal.
Combine with the imp to get a Mass Dispel that burns 1 magic effect from an ally and up to 5 other allies nearby the person you dispelled.
Combine with the Succubus/Incubus to wear a short skirt, and to make all spells slow the mob by 25%, if it can be slowed.
Combine with the Felhunter to make all spells have a 50% chance to silence/interrupt the target you damage for 1 second.
Combine with the Felguard to make all spells have a 50% chance to stun the target for 1 second.
Also during this spec your CD makes you become Gul’dan himself and do something that Gul’dan can do. What that is I don’t know, but something that he can do.
A tanking spec for Shamans using Rockbiter weapon and Earth Elemental magics.
I like this, but I would also argue that you heal by yelling at people. That would be hilarious.
I’d seperate Unholy into Zitbuster and then the other one would be the actual Necromancer it should be, Master of the Undead army.
I’d like Discipline spec to be renamed into Disco, with the only thing they do is force everyone and everything into disco dancing, including dropping a disco ball, too. This includes raid bosses. The only thing they say in voice is “Disco Disco” and they dance disco dance while healing.
I’d give Druids a fifth spec: “Fish” spec. The only thing they do is flop around like a Magikarp when they’re not in the water. That’s literally it.
I’d redo Survival Hunters as a healer spec, with making the current Survival spec into 2 other specs instead: Melee version would be called Spearman, the ranged one we had before would become Bowman. I’d also give them yet another new spec called “Trapper” that all they do is just throw Traps at people, just like the Trapper Assassins from D2 or PoE.