For a system like this to work, the algorithm would have to check what players are reacting for each move the target does.
Monster cast x skill1. Tank turns a tank buster into the melee. Melee die, and do less damage as result. Melee get a bad grade because of it.
Expected result : only tank gets hit (cleave)
damage mitigation : +points
no party members get hit : +points
If 1-2 party members (non MT) get hit, - points to those players
If 3+ get hit, -points to the tank.
Monster cast y skill2. Subpar healers can't keep the group alive, dps die due to AOe's and have lower damage as a result. Again, bad grade received.
Aoe damage, is there damage mitigation? +pts for whoever cast the mitigation skill
Heal and overheal is calculated on the next 5 seconds to provide a score.
If death by unavoidable attack, healers get penalized, if death is by a avoidable attack, the players get penalized.3. Primal fight. 4 people dead. The remaining 4 are able to clear, but take more damage as result of the fight lasting longer. Again, receive a bad grade.
It's a wipe, why would it matter? As long dps can see they were the cause of the wipe, the system is doing it's job.4. Poor DPS can't meet the DPS check. Healers and tanks die as result, get a bad grade for damage taken or not clearing.