i really enjoyed the 10 button setup in wildstar.
you had way more skills than that but you could only "equip" 8 + class skill + trinket skill



It really did have a lot cleaner feel to play with limited actions, and was kind of neat having multiple saved setups that you could swap out for different occasions.
FFXIV could never pull it off of course, I think just the basic healing spell lineup for healers is like 6+ buttons already
but i really do feel like less is more in a big way for making MMOs more enjoyable for the majority

i mean the physical dps basic combos are kind of silly as they are now. You have like 6+ buttons for one combo all usable at any time but all completely useless when it's not their turn.
take a page from newer games and have the buttons just change function as you progress through a combo. Astro and Monk are proof that FFXIV already has the coding to support it.

dps don't really need like 5 different cooldown skills that all accomplish basically the same thing as well. A damage booster and a resource booster would get across the same point

same deal with tank cooldowns, they all have this big line of cooldowns that they just go down as tank buster skills roll out. Just figure out how often you want tanks to be able to reduce damage and give them like 2 to use with appropriate cooldowns

if they wanted to they could get every class down to like 20 buttons or so i would imagine. Cleaning up cooldowns, combos, and skills that are super similar would go a very long way