It's important for Snap Shot, since it starts at threatening at 5', which you can't 5' away from if you want to take advantage of.
I'll be changing it to purple, as playtesting it on my PFS Gunslinger has proven that it's worse than Weapon Specialization except on Gundolons, Guns Akimbo builds and TWFers in general and even then. A little math and critical thinking on my part would show that it's pretty much a trap.Completely unrelated but, Cieyrin, why do you value Hammer the Gap so much? Even an 11th-level Gunslinger with Haste will only get 6 damage if he hits every shot. Aside from some edge-case build where a level 16 slinger is shooting 2 Speed revolvers with Rapid Shot (which would be +45 over 10 attacks), it doesn't seem worthy of "light blue" quality.