Good question. We decided to dig into all of the dots and found they worked pretty inconsistently. (Consistency isn't always critical because it does lead to a certain amount of homogeneity, but too little consistency can just be confusing too.) We made a pass at all of the class dots and made them snapshot crit chance. This will have implications in any simulations out there.
However, this has some implications on the Unerring Vision of Lei Shen trinket. We’re tentatively fine with the idea of you seeing that proc go off, and reapplying DoTs which crit for their whole duration, in most cases. There’s a couple cases where those periodic crits cause other effects, which end up being very powerful. For example, a Balance Druid can now apply Moonfire and Sunfire, and pretty much chain instant Starsurges for 15 sec, many of which are extending that Moonfire and Sunfire, probably out to 20-25 sec. That’s extremely strong, but we’re going to try leaving it alone for now.
The one which is simply too strong to leave is for Shadow. For Shadow having Unerring Vision and the PvE set bonuses would mean that every SW:P tick guaranteed crits, so spawns a Shadowy Apparition, which has a 65% chance of extending SW:P and VT. And the VT ticks have a 10% chance of spawning a Shadowy Apparition as well. And both can trigger a mastery tick, both of which can also spawn another Shadowy Apparition. The net result is that the feedback loop is so strong that in attainable gear, it’s net positive, resulting in SW:P and VT lasting forever (or at least until you get very unlucky and get a long string of failed procs, which will probably take several minutes to happen).
Since 100% crit SW:P and VT that never need to be refreshed is a wee bit too strong, we’re building in a failsafe. We’re fine with you getting a normal SW:P/VT duration of all crits, but not forever. When Shadowy Apparition extends SW:P and VT, and that DoT has already lasted longer than its normal duration, it will recalculate its crit chance. The result should be that the trinket procs, you reapply SW:P/VT, and get 18/15 sec of crits, then they drop to your normal crit chance.