Quote Originally Posted by Kuwagami View Post
it doesn't. With that said, since crit has a non-null base value for a tank, unlike DH, you'll get more consistency from more crit than from adding DH imo.

I may very well be wrong, but the only thing that would change is the order of melds, making tenacity and DH more desirable than crit. And since the trade-off of tenacity vs DH is neglictible, you would rather meld more tenacity for the increased survivability. Which would leave the choice between DH and crit only on the few pieces not capped in tenacity
Crit increases your critical damage and your crit chance. So it will scale your damage like:

(Crit chance)(Base damage*Crit modifier)

That means it will grow like a parabola since both the crit chance and modifier are linear functions of the crit stat. It will scale much, much slower at low levels and then scale much faster at high amounts. Direct Hit scales linearly so it will always be the same value=>% DPS increase it is now.