Greymane late worgen carry Unleashed build.

This build is based on late game where enemy team has big cc (like Jaina and Kerrigan) and doesn't have burst sustain healing (Uther). He's aiming into poke dmg on its q quest Incendiary Elixir   and lvl 20 talent Unleashed   where with each stack you can kill enemy mages faster and with 2 stacks (3 kills with Go for the Throat ) Tracer carries should better hide. Unfettered Assault might be a suprising choice but for good Greymane player it is best option if conditions described in 1st sentences are made because of following reasons:

1)Escaping in human form is hard if there comes a big Jaina cc or enemy team has Artanis, so in most of the cases going into worgen and escaping with its Razor Swipe saves you mostly but with Unfettered Assault you have 99% chances to escape and, well- kill them later.

2)Worgen form makes some more damage and without Unfettered Assault you will be sentenced for human form to deal some serious damage when enemies are not close to each other. Above that with Razor Swipe's low cooldown moving around to use Unleashed is way easier and makes you possible to carry late games.

3) When enemy team has some serious tank like Diablo or Blaze and you decided to pick GftT you need lvl 16 Alpha Killer   which is useless in human form, as description says so good mobility in worgen form to use it is worth quitting old habits connected with Ctrl+1 lvl 13 insta pick.

4)Diablo might be serious problm, same as other stun cc like Kerrigan or Stitches and Garrosh. I gave those heroes as example because of many uses of Unfettered Assault  . After removing Relentless Predator(13.09.2016 RIP, we all remember) good cc against Greymane makes big problem for him, so Unfettered Assault   is good exchange. When it comes to Diablo-he pushes you out of the fight into the wall, making you useless for~2 or 3 seconds, but with this talent it won't be that easy for him to separate you from his teammates, when your q ability has almost same range as his and lower cooldown. Kerrigan- her w+e combo is very frustrating for every player. With q update you will be possible to avoid it much easier by escaping it on some side(left-right), going throug her e(in front) or suprising her by passing her' w with it(Kerrigan) and killing her*. Stitches and Garrosh- this is my best part. When you get pulled in by Hook or Throwed by Garrosh into enemy team you are usually presumed dead. But with your q mobility talent you can suprise them, killing their backlanes before they would even realised.

This build needs players' prediction if it will work in match or team won't lose some serious damage. In the beginning it's focused on ending kills and Coctail poke, finally at 20 lvl the real fun begins. I hope  800 games 60% winrate Greymane' player experience will be found useful by every reader (I am not boasting, I'm just prooving my credibility).

*W+E Kerrigan avoid scheme

                 Front

Left<----Greymane---->Right

               Kerrigan