I've heard people compare the speed they can go through a certain skirmish (per stats) if they weren't using the Combat Analysis plugin.
For your tank scenario, the survival skirmish with endless waves of enemies provides for that.
So skirmish stats provide what you are seeking, although for healers, the HPS from plugins is probably more useful, but applied to a uniform NPC (you hear healers asking tanks what their incoming heal rating is after being surprised at an unusually large crit).
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