Personally would rather have more buttons than less. Those suggestions you made do make sense in some way but I still prefer them to be separate buttons. Imo having them seperate is more fun, engaging and immersive since then your button is reserved for a specific action/command, I don't consider summoning something the same as commanding your summon to do something, thus having separate buttons makes more sense to me and I enjoy it more this way.

The earthly star comparison isn't really a good one imo immersion wise since there you basically cast something that doesn't do anything on its own. It's dormant until time goes by or you trigger the ability, here it makes sense that it would be the same button you'd tap for it to trigger.

The button bloat-ish combat is something that's atm fairly unique about FFXIV and it's a big reason why I prefer this game over other major MMOs.