Between asking a Healer to do some DPS with having a Healer not DPSing, which would be more logic and more real???
We have Trinity for a reason, we are all given a specific roles to fulfil. Anything outside the already appointed role is just a bonus and should be treated as such. Much like asking Pal, when he has established a decent threat, go and help with the Healing as the Healer is busy with Dpsing...So much for a reality...
