Why Crit for tanks?

[Mikey_R]

So if you're doing stuff with party, damage is always the option, which means crit has prio and after that its going for dh/det balance.

However if you were to do solo challenges, i believe tenacity is actually the best option.

Tenacity scales so slowly, you would still be better off with your normal melds. The mitigation you have is going to be more than enough to cover what you need and in most cases, you do still want to win as fast as possible.