I second this.
I understand there are less tanks than healers, so they try to give maximum incentive to players to pick up any of the tank jobs, but i do feel like the mount thing is unfair, and a bit overboard to be honest.
There are many other ways to incentivise players to play tank in DF and i wish they would give it more thought.
So yes, in my opinion if tanks can get mounts just by basically playing the game, i think it should be the same for healers and DPS.