A possible solution to button bloat

[Rilifane]

SE would need to think up and balance a ton of new skills for every class, that's too much work.
I'd prefer something not unlike the old cross-class system: as you level up, you can check a certain amount of skills to take with you into low level content. Not too many, but at least a few that are important for your class to at least somewhat work.
Just to give an example: you can take 2 skills with you at 50+, 3 at 60+ and 4 at 70.
So when you're 64 but get a Haukke Manor, you have your 31 toolkit + the 3 higher level skills you chose to take with you.
I think it's great that you have access to all your role skills even in Sastasha but many classes feel incredibly clunky without the 2 or 3 higher level skills.

Also I much prefer introducing new skills with every expansion while at the same time getting rid of some old ones through pruning.
It's something that really bugged me about the two last WoW expansions... lots of pruning but NOTHING NEW. The character just feels stuck.
Gameplay evoles and SE keeps an eye on this. So over time some skills just fall behind others and rarely get used. Get rid of them in favor of new ones. Give the classes the chance to constantly evolve, each expansion adding a new flavor while getting rid of an old one.
Consolidate some skills through Mastery into one button, maybe switch an older skill of a 3 part combo for a newer one while and get rid of the old one.
Cure3 and Medica come to mind for WHM. Adjust one skill and get rid off the other.
Or Aero2 and Aero3. Something like: if Aero2 is on the target, the button lights up and by pushing it again it instantly and ogcd changes the dot on the target to Aero3 (with the cool Aero3 animation!) and spreads it to nearby targets. You always have the option to press it a third time for having both dots on one target. But that you only have one button for your two dots and only the short animation lock in addition to one the one gcd for Aero2 compared to the cast now.
I think stuff like that would be possible for a couple of skills.
And if a skill is really outdated... well, time to say goodbye. Sure, some skills will be missed but it's still preferable over lacking class developement. You get something new and (hopefully) cool for it in exchange.

[Xbob42]

It's something that really bugged me about the two last WoW expansions... lots of pruning but NOTHING NEW. The character just feels stuck.

Right?? It was my #1 problems with the game. Your character was getting weaker and weaker every expansion instead of more capable. Generally your numbers go down after every expansion due to a secondary skill reset, which I guess is a necessary evil (although I think FFXIV would do well to let us keep our skill speed at least...) but that was always offset by new abilities that "completed" your class. With Legion and BFA, you just plain got weaker. It was awful. Imagine going into Shadowbringers and you're basically reset to your Heavensward class. Not Stormblood, mind, but they prune you back to Heavensward. That's what BFA was like.

I want to avoid that kind of expansion at all costs.