Constructive Solution to Crit Problem.
I’m a scholar, thus I don’t take stance.
Hmm, that’s rather interesting. I sort of like your idea.
Personlly, I would change your suggestion by one small detail. Instead of tying vitality to crit defense, I would tie toughness to crit defense (if it is to be tied to a stat at all). Generally speaking Vitality is used as a defense against large amounts of condition damage, and Toughness is used as a defense against raw damage — making one stat mitigate both seems like it might be slightly unbalanced.
You would also have to make sure that npc mobs come with crit defense. The DPS meta only really dominates in PvE. You see a lot more build variety in the other game modes.