Tanks are fine (show your support so they don't change them)

[DrCynapsis]

Also, I never told a healer that they needed to DPS. I just sat quietly in frustration doing my job.

I rarely badger them when I see Healers play pure healing only. I use it as an excuse to push a more aggressive play style and see if they keep up. If they pipe up I usually respond with a rant about party synergy.