I am in a similar situation. I re-rolled as a Cleric, twinked my character, but can never feel at peace in a group that continuously pulls one after another. I'm always the one that has to say "oom - hold up on pulls, please" while feeling like a wrench in the group. How do I keep my mana flowing and keep up with fellow group members?
I'm level 12 currently, and what I do is cast Center on anybody who is at 80% health, sit, wait for two ticks, for Center cooldown, then do it again to anybody who is at 80% or lower health.