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.
When I was playing WoW I had a 27 button gamepad, and a 16 button mouse, and I still ran out of keybinds. You don't need that many for PVE, but you need everything keybound if you want to compete at high levels in PVP.