This just popped into my mind but this would actually be very possible.
Dragonball Z was my favourite show as a kid and really all the moves can be separated and put into a hotkey MMO.
The worlds could be massive and the bosses could be dynamic events.
Obviously a new threat keeps showing up so they could keep adding "raid" tiers but really with this concept I think developers could truly go crazy and innovate, leading us away from trinity style gameplay.