Maybe a general pie graph type thing I would not or ever display numbers for pve that would create some toxicity kupo <3 but I am not against a simple #1 was such and such #2 was such and such...that could be fun.
Anything can really breed toxicity if you think about it enough so it is a slippery slope kupo <3
Could bring in achievements like "Top #1 dps for x amount of something" ...not sure how that would work with tank/heals..perhaps in raid settings...again slippery slope though kupo <3 must be taken with much caution :p
Course again with something like that it could be cheesed very easily with 2 dps roulette playing the "My friend needs this achievement so I will faceroll this dungeon" type thing etc..
