We've known about its ability since it was unveiled. Strong Jaw, boosts biting moves.
Unless you think it just randomly loses its signature ability.
No, I'm saying it could. It could also have bad Stats. You get the point. Judging a Pokémon's viability based on looks never pans out well.
I feel like I should mention something here, but it's probably not worthwhile. One of the earliest rumors about X&Y mentioned the existence of a Rock/Dragon Fossil mon. It also mentioned the following things:
There is a "Z" mon, a Rock/Water Karken-Turtle thing with rock formations on its body. Sky is "Y" and Forest/Land is "X" (Axes), hence it holds that "Z" is Sea (Depth).
The legendaries have "sub-ordinate" Pokemon with them. Yveltal has two Dark birds with it. Xerneas has two bug-like creatures with it. The Z mon has two more smaller turtle with it.
Kalos' backstory: Pokemon trainers fought wars with their Pokemon, therefore destroying peace in Kalos. Yveltal, the Destruction Pokemon, razed kalos to cinders and put the wars to an end. Xerneas, with the help of its "subordinates", rebuilt Kalos with its powers.
Note to mods: Like I said, this is probably a bad idea. I just felt like putting it here. I saw the rumor on 4chan, so it's as legit as Fennekin being Fire/Fighting. If you feel this is crossing the line, delete this post.