If they wanted it to be a successful console game, they’d have to dial way back on the number of spells and abilities.
Even with schemes like L2+square, L2+R1+square, etc. you just wouldn’t have enough keys to map everything.
More games should use FFXIV’s cross hotbar system. It’s really, really good. I don’t see why this couldn’t work for WoW too.
Basically it’s hold L2 - you get 8 buttons. All of the dpad directions and the four shape buttons. Holding R2 gives you another 8. From there you can either hold R2+L2 for 8 more, cycle with R1 to another set of 16 or double tap either R2 or L2 for 8 each. More than enough for anything. People clear ultimate content (hardest stuff) all the time with controller and it’s just as normal as mouse and keyboard.
More games should follow FFXI’s console port and support Keyboard and Mouse. It’s not like the console isn’t running a flavor of Windows or anything.