If it's alright I'd like to give you an example from my own experience. I have pulled mobs as a dps and healer quite a few times (and rarely gotten a negative response, can still count on one hand). When I have done this a few things occur. I take a few hits and then the tank picks them back up. But in those few hits I use arms-length and give a slow debuff to the mobs, thus saving the tank the need to use that cooldown and I've helped them mitigate some damage with my own health bar. As a dps (I often play melee) I have my own hp regen abilities and as a primary WHM user I have assize to both damage the enemies and delete the damage I or a dps took. More abilities are being made use of then otherwise, health/mitigation is being conserved on the tank and allowing them to handle the pull easier.
You've mentioned the RPG aspect, well when I play single player RPGs I want to make as much use of my units as I can. Is that not what I'm doing in this example?
I'd like to clarify something here. If by speed running you mean double pulling, that's not speed running. The two are very different. Also double pulling isn't me wanting out of the instance sooner, I just have A LOT more fun when double pulling. Largely because there's no threat in single pulling. There's no chance of dying and no need to use more of my abilities. On a double pull I have more freedom to actually play the game and press the many buttons each class has.
