We really need some button pruning.
If skills are mutually exclusive or need a specific skill to have been executed first, just merge them. Leylines/ Between the Lines, Dream within a Dream/ Assassinate, Third Eye/ Seigan with Merciful Eye still on a seperate button etc.
And PvP combo system.
That alone would free up plenty of buttons to make room for actually interesting skills instead of keeping pointless button bloat, deleting nice skills and giving them back 10 levels later with a new animation.