I’d love to see rank 13 someday tbh. They could then release final classes for each tree and that’d be the end of class progression but NOT level progression.
To accommodate harder contents that will be necessary for new chapters, they could create a transcendence system (RO2–style master level, if you will) where you can remaster earlier ranks (let’s say up to rank 4 classes).
But beware—transcendence system is usually poorly done. If they provide ways to give more skill points, that will be the end of it. I think extra stat points are OK.
Beyond that and I honestly have no idea. If IMC faithfully continue and expand the lore, they will need to give players new progression possibilities as well. Unless they decided to finally end the main arc (Laima and her revelation thing).
More:
The final classes must be extra, flashy, and scream “look at my muscles.”
Or of course…
If new classes aren’t a good idea, rank 10 to 13 can be reserved for remastered circles. That’d be acceptable too.
You can only choose one class to be remastered.
Example: Master Pyromancer adds more low-damage dots at rank 10, more utilities for Fireball at rank 11, a shiny new spell at rank 12 OR upgraded Hell Breath (stationary, fire-and-forget Hell Breath, anyone?). Something like that.