So, I ran with the Rune of Re-origination throughout our normal-mode cleanup raid tonight. I will first detail the summary of the results before diving into the details.
Summary
The Rune of Re-origination is terrible for hunters.
Gear configuration
I ran in a configuration that had 8800 crit, 6800 haste, and 2300 mastery, which simmed well in FD. On proc, this resulted in crit rating of 17900 (over double my previous crit rating). The test was done in a 25 man raid with full buffs and boss debuffs in a 3.5 hour raid.
ilvl was 526
Log:
World of Logs
Uptimes:
Reorig: (min: 11.2%, max: 31.4%, avg: 18.1%, >30%: 1 bosses, <15%: 2 bosses)
Juju: (min: 14.2%, max: 35.4%, avg: 23.7%, >30%: 2 bosses, <15%: 1 bosses)
Reorig specs:
1467 agi baseline
Proc: -6800 haste, -2300 mastery, +9100 crit for 10s.
Bad Juju specs:
1552 mastery baseline (reforged 620 to crit or haste, which allows for the player to create synergy of 9:6 mastery:crit)
Proc: 7333 agi proc for 20s, resulting in 1686.59 agi normalized (23.7% uptime)
Analysis
Because of synergies between crit and haste and crit and mastery, we have known that stacking pure crit is worse than dividing secondary stats between crit and haste or between crit and mastery (i.e., you get more bang from your ilvl buck by not stacking any one stat--they harmonize together in pairs). From that statement alone, you can probably gather what the experiments showed on the World of Logs parses. What shows up in the log is that every single time the Rune proc'd on a fight like Iron Qon Normal (where there is only one target being attacked), the dps line either stayed flat or went down. The proc from the Rune was a dps loss for me on almost every single cast. The exceptions to this loss were when I was under the effects of some other beneficial cooldown.
The only beneficial part of the Rune is the passive agility. The proc just shifts secondary stats. On normal, this means the pro of the Rune is 1467 agi.
In contrast, every other trinket dropped from ToT that we would want has either the same passive agility (e.g. Talisman) or more normalized agility (e.g., Bad Juju and especially Renataki's). Despite what FD and Simcraft seem to be telling me about the ranks of these trinkets (right now, Rune > Talisman in both simulators), I cannot think of a good mathematical argument for why the Rune would ever beat an equivalent ilvl Talisman. The Talisman adds stats with its proc (stacking haste buff, similar to Renataki's agi one). The Rune simply moves stat weights around and does so in what we've modeled as the worst possible way to allocate secondary stats (loaded onto a single secondary stat). Even if Blizzard does up the proc rate again (to let's say double the current proc rate to have almost double the average uptime of Juju), because the proc rate is at best an equivalence (but more likely a loss considering it stacks a single stat), the trinket will gain no additional utility for hunters. Meaning, unless Blizzard changes the proc rate to something useful for hunters (e.g., by adding the mastery and haste totals onto crit while keeping the current mastery and haste), the trinket is only useful for its passive agility.
Or as Tehstool has so eloquently stated before, "The Rune is terrible."