hmm I mean for me it would be fine if they reset all levels but they could just add all of your exp to a new level system so if it would be the old level system all level 100 players would be level 10-20 or so.
they just have to give us a reason to grind.
also the old upgrade system was way better. now that the game isnt p2w anymore the old upgrade system would fit so good rn.