How do we feel about tank damage right now?

[Shurrikhan]

The problem is how you "scale" this worth. Let's say the gap between an average DPS and a top DPS is from 10k to 15k (made up numbers), you can't really have tanks ranging from 5k to 10k, because it would make the skill ceiling too high. However, having tanks ranging from 5k to 7,5k would mean that, for both roles, you'd have a 50% increase from average to top.

At risk of being especially redundant, imo, the % variation within one's own role is not what matters; the flat contribution value, when including both indirect (healing GCDs saved) and direct output (damage), is. Otherwise roles benefit equally from any equal increase in player skills.

If you need a more in-depth explanation, see any of the former posts, including the one you've quoted, such as just a few sentences before the chosen line.

But for two roles to be equally rewarding of mastery, they can't just have equal % gain relative to themselves, but also to each other.