This creates even more design problems than it solves. These NPCs would be a DPS/HEAL robots with crappy and limited AI, never doing any bigger mechanics and never being targeted by them. So even more responsibility falls on a single player. And what would determine their DPS/HPS output? Fights have different strategies where these things differ. Like Stone Legion for example: some strategies call for AoE burst adds on certain timers, some call for single target DMG and you can fuck up both of them if you apply DPS incorrectly. Not to mention if you undertune these NPCs then they become dead weight, if you overtune them, they will carry you. It's an undoable thing, too many variables to consider and system would be too limited.