This mon looks pretty bad in terms of competitive (even in PU, you get the likes of regular Muk, Stoutland, Mawile, Relicanth, Dusknoir, and likely new additions such as Slush Rush Beartic, Toucannon and Alolan Sandslash that do any of its likely jobs better (and considering that it won't likely be the only Fighting-type PU gets this gen, it sucks in that regard too)). It doesn't get ANY form of priority, and defensively I don't think you could get a worse typing. While yes it does get a Stealth Rock neutrality, being weak to several prominent offensive types such as Fighting, Flying, Psychic, and Fire isn't good whatsoever. However, it might see use in very lower tier Doubles due to high attack and Trick Room. Of course, not in a tier where Conkeldurr exists, but still.
Yet despite this, and its really dumb design (though I haven't seen it in motion yet so that could change), I'd actually use one. That typing is bad defensively, but its unique, and offensively its rock solid, combined with some decent coverage options. You get it early on, and its one of the only Ice-types you can get for quite a while. I also love Crabrawler's design, and in general I just love crabs. Even if it turns out to be the worst mon I've ever raised in a main series game, it'll be fun to experiment with. Of course, I wouldn't use in my main playthrough due to how risky it looks, but maybe if I can obtain Pokemon Moon, this thing will definitely be apart of my team.
On a final note, move tutors would improve this mon, especially if it gains Knock Off or a priority move, and possibly Drain Punch to help an Assault Vest set. If Pangoro could jump a tier or two because of stuff like that, I can't why this can't do the same thing.
