From a healer's perspective, sometimes I can or can't keep up with DRK (or any tank) that is not in tank stance for a number of reasons:

- That stance gives you a defense buff. Without it, you'd sometimes take more damage than necessary.

- Some tanks want the healer to be included in fast runs. Tanks turn off stance, healer does a dps spell one time too many, tank falls. Some tanks forget that Cleric Stance has a CD.

- The tank's HP is lower than it should be. No tank stance, all STR Attributes, STR accessories. I'm out of MP because of the tank being an MP sponge.

So, yeah... That's why I'll NEVER dps as my healer. Nope. Too many times where I failed to keep the tank healthy because of it.