I wouldn't mind some battle mechanics like fatigue and hp/mp decay through it but the mechanic would have to be clearly identified visually for healers or supports to help alleviate it and manage it but the whole system would really need to be reworked entirely into a different type of content to bring actual resource scarcity and forays into dungeons or hostile territory, rather than dance fights. Just adding a debuff that grows over time or forces healers to overheal else the dps are going to go mad at them for losing damage, on top of the current system, feels frankly kinda like a punishment.