Cho'Gall was allowed during the Enter the Storm Qualifier for North America and 2ARC actually picked the hero during their game vs. Stellar Lotus! If you missed out on the match you should check it out was quite a bit of fun :D
I watched that game, and it was hard to tell the extent to which Cho'Gall was effective versus how clumsy Stellar Lotus was at times with their positioning. If you watch the late game teamfights closely, you can see that SL were repeatedly exposing themselves to getting crushed by Kael's Chain Bomb.
This was a great game, Gall is definitely a high hero damage dealer. I love playing Cho how ever, he's really good in regards to small maps. I always feel like it's 4v5 in the bigger maps.