its not the same, while DRG rotation for expample still encourage buttom diversity while upgrading certain skills for proper management of you rotation putting 1 skill after another on the same buttom will afect gratly buttom diversity compacting all GCD in to a few buttoms increasing the spam rate for no reason.
i will put this together, first there is no problem of buttom bloat, the OP probably didn't use shortcuts properly to claim that, tanks have the less amount of ofensive skills and most defensive skills and stuns are pretty much situational, i been playing this game for 6 years now and they didn't go in to a problem of there is to much buttoms and i still have shorcuts i can use if i want to and i have unused, so is for laziness or missinformation about mapping your skills properly.
the same comunity that make several dutys and dungeons get nerfed bcs too hard for they braincells yeah, the same comunity that are going to get new game plus with a very easy option, and how savage as become more easy since alexander.
you can archieve the same with skill upgrades, inner beast and fell cleave for example are a good example, if the devs use more this, animation diversity will be greatly increase depending if you are sync or not, upgrading animations as a reward for manage properly you rotation like DRG ones is a great way to archive that and obviously stop creating inner release windows everywhere.
removing skills will be eventually thing for whatever reason like what happen to dark arts or what they did to delirium , scourge being sustituted by bloodspiller rotation wise so it won't make anything more easy until you start consolidating more and more and more until you have full rotations in 1 single buttom and start calling this kingdom hearts online.