Parry...

[Kitru]

Unlike parry, vit actually increases your eHP and that is what you want to gear for, after all.

eHP isn't everything. Parry would be an absolutely amazing stat if the returns on it weren't so low, which is the problem. The first argument (RNG mitigation) is only a factor because of the second argument (very small returns). It's not a question of mean mitigation not being a valuable aspect of tanking to improve, but rather, potentially, the improvements to mean mitigation not being worth the opportunity cost paid to tank DPS.

Personally, I haven't seen all that much of a significant increase when geared for det/crit compared to straight up parry which really just tells me that the comparative value of all of the secondary stats is equally miniscule. If they're all equally miniscule, then I don't really see a point in gearing for damage rather than mitigation since mean mitigation *is* a higher priority for tanks than damage is (the basic priority in burst heavy scenarios that the ARR devs seem to prefer is eHP>mean mitigation>damage).

As to STR v. VIT, VIT should still be your priority because it doesn't suffer from any of the flaws that Parry does while simultaneously operating on a higher priority goal for tanks. Even if you want to make a case for STR contributing to mean mitigation by increasing parry effectiveness, the contributions of 30 STR aren't going to make nearly the difference than 30 VIT is (not to mention that increasing STR actually increases your relative spikiness, interestingly enough, whereas more Parry decreases your spikiness).