It tells you in the skill description how much you mitigate. Having it appear in flying text is just going to be annoying as it produces, well...more text that is necessary as opposed to the numbers.

As for tanks' DPS, if a tank is more focused on DPSing then tanking, perhaps they shouldn't be a tank anyway. I enjoy playing tank because I know I gain lots of control on a fight. Plus I pretty much have people by the balls because they need me.