What they mean by "change the damage calculations of tanks"?

[Tyrial]

This doesn't quite seem accurate, full vit 210 War should have around 21-22k HP out of defiance, and full vit war not doing 1200 dps.. Unless your talking about future item levels.

I don't think War having more HP would affect attack power. It would be based off vitality stat if anything, and all 3 tanks would have the same vit stat since they share gear (well, maybe not eso gear but it's all the same vit stat). If attack power was based off HP and not Vitalty, then something like thrill of battle and defiance would turn into dps cooldowns.

Not once in his post does he mention HP being linked to attack power...he says if VIT became the damage modifier it would throw things out of balance if HP scaling was left as is.