Overmeded vanya or royal chest?

[Finals]

You can have a 90% crit rate, but try to save your tank and that 10% doesn't happen, your tank dies. This can and usually does end the run unless the other tank is somehow unscathed. Sch should aim for crit as a secondary because they get a large benefit from a crit. If its for a whm, I can't in good conscience recommend crit over raw det for consistent healing. Your calculations also don't take into account that a crit can cause over healing, making your actual hp/time much worse. If you are only going to heal when you think a crit won't overheal, then I feel bad for your tank because hes in the red zone way too often and can't make any mistakes.

However, MND > all secondaries for both classes.

While your sentiment is correct, the probability of this occurring is almost 0 (namely 1-((1-percent crit)^(number of casts)). However, the initial question was is 5 MND better than a loss of 18 Determination and 27 Critical. In this case, +18 Determination and +27 Critical is better than +5MND. The game is realized upon mathematics, thus forgoing calculations for belief is wrong. If you have 90% crit, you'll actually crit 90% of the time over the course of a long fight. The argument that you'll never crit with crit is ridiculous.

Also, the argument isn't about whether 1 MND is better than 1 crit. This is obviously false. Each stat has a weight and we must note these in order to min/max our character if that is what we wish to do.