The ratio of tanks and healers to dps is very lopsided. Tanks and healers are desired but its become resented (if my previous posts about pug attitudes is any indication).
I've seen these suggestions before:
1) Tank and healer NPC henchmen
2) And getting rid of tanks and healers altogether
The second one I find interesting because thenoisyrogue suggests players can alternatively be responsible for mitigating damage (no healers present) and "locking down" an enemy (no tanks present) while the rest dps.
Where I think this falls flat is this is what PvP is. PvP for all its arenas, battlegrounds and world crop-ups is quite often a one on one affair where the player is responsible for keeping themselves alive long enough to kill the other person.
Do you remember the complaints about the "PvP" portion of ToC and Magister's Terrace? I'm not sure what the specific complaints were but I imagine they had something to do with not being able to have stuff tanked while healers healed and dps dpsed.
As a healer you don't know how many times I've buffered someone's failure to be their own holy trinity. I've seen mages try to tank, rogues miss interrupts, hunters forget to feign death.
Very few people like the burden of personal performance causing success or failure placed on them. Controlling a cube didn't require tanks or heals (did it? I can't remember) but how many people failed at that.
Players do not want to do those very things that make healers a little less necessary. Even things like maximizing their dps instead of being happy at #9 could put many of us out of job.
And let's not forget since folks like to stand in fire I've been invited to things as soon as I log on.
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