We have a lot of Cleric Stance lovers in this thread.
The point of my comparison is, again, more something like this.
Tanks rarely swap between stances mid-battle. Before everyone chimes in and tells me about the time their WAR turned on Deliverance to help with the DPS check in savage, I get that it HAPPENS, I'm just saying its rare, usually a tank is in a particular stance. Further, when tanks do switch stance--let's say, from Tank to DPS--they don't become fragile wallflowers that die in one hit, they are still hardy with a lot of HP, just squishier and can't take huge tankbusters.
The stance swap mechanic with healer, on the other hand, is meant to be in and out of the Cleric Stance many times mid-battle. Further it's very dangerous. (At least for all the unskilled pleb healers who don't have the mechanics on lock huehue amirite guise?) While a tank in a DPS stance can still generally take hits alright, a healer in Cleric Stance just CANNOT cure effectively at ALL.
If we really want to talk about leveling the playing field, it's not enough just to point out "there are stances"--we have to think about how those stances are actually used in play.