Those 20 buttons do a good job creating the illusion of difficulty. It’s still largely memorization and using X button to unlock X button to unlock X button via their systems.
They’re different playstyles. WoW uses a priority system with lots more procs and the like while FF14 still uses rotations.
To the simpler folk more buttons automatically = harder, but in reality your choice is usually between using the 1 or 2 optimal buttons at any given time in either game.