As for PoJ, you take it because you're moving on the majority of ICC fights. Only a small amount of movement time is required to justify a dps increase over 2 points in conviction. Math is fairly straightforward.
Two percent crit is a 1% threat increase, this is very linear and easy to map.
PoJ is harder to model, but we start by saying it reduces our "movement time" to 85% of normal for a given fights. The value of runspeed is thereafter found by the amount of time spent running in a fight.
Tank A is PoJ spec'd. All other talent choices remain standard.
Tank B isn't PoJ spec'd. His threat can be said to be 101% that of tank A's.
Time spent running will be averaged over the course of the fight. It is given as a percentage of the total fight time.
So, for example, a fight with 20% time spent running (80.8% "Patchwerk" or non-movement tps) would only be 20*.85 = 17% time spent running for a PoJ tank (83% "Patchwerk" tps). Determining when PoJ is better relies on finding the breaking point in run time. It's a system of equations which is simple highschool math.
Equation 1: (1 - TSR*0.85)100 = % "Patchwerk" tps for PoJ spec
Equation 2: (1 - TSR)101 = % "Patchwerk" tps for non-PoJ spec
Set equations equal to one another:
(1 - TSR*0.85)100 = (1 - TSR)101
Solve for TSR (time spent running):
(1 - TSR*0.85)100 = (1 - TSR)101
1 - TSR*0.85 = (1 - TSR)1.01
0.99009 - 0.84158*TSR = 1 - TSR
0.00991 = 0.15842*TSR
TSR = 0.00991/0.15842
TSR = 0.0625
Time spent running is 6.25% of the fight. That's a trivial number and basically translates to "any fight with movement, period" in average Joe terms.
Current movement fights include:
Marrowgar
Deathwhisper
Gunship
Rotface
Putricide
Blood Princes
Blood Queen
So, 7/9 fights it's worth it.
EDIT: This analysis doesn't include tangential benefits like "getting out of the fire faster" and "being in range for a taunt when you really need to". But the fact that any movement is justification enough to take the talent more or less eliminates the need for anecdotal evidence.