Honestly OP even though I kinda agree with the idea behind it (because there is nothing more frustrating of having someone who was dead the whole run get nearly everything of the loot at the end) I doubt that this can be implemented in a way to be fair. How will the system judge if you have done good or not? It would need at least three different ways (for Tanks, healers and DDs) and then what would be the right way? Increase the chance if you are just doing your job by simply tanking or healing? Or would they need to DPS too? What happens if a healer or tank let people die on purpose to let it look like they are not carrying their worth? Or just simply a bad healer that lets the others die from unavoidable damage.