I'd offer a few things to consider being a Hordes player (albeit a noob) and a Circle player.
The first thing I would say is try to get a 2nd beast into the list somehow. In Hordes your war-caster's fury is fueled by your beasts generating fury during their turn. If your opponent is able to kill off the Pureblood your S.O.L.. Even if the Pureblood isn't dead you're only going to generate a max of 4 fury that turn. With Kromac being fury 7 you're handcuffing yourself if that's your only source of fury.
Secondly, I'd replace the Pureblood with either the Feral or Stalker. The Pureblood is probably the worst of the 3 heavy Wolfs. It's not that the Pureblood is bad per say, it's just that the Feral and Stalker are better. The only thing the Pureblood is better at is it's RAT and spray attack (and it's the best model of the three, IMO). The spray attack is most useful for taking out infantry, which you wont see too much of at 15pts. Once in melee it's just not as powerful as the other two. Unless you've got a particular strategy in mind with it's animus I'd say take one of the other 2 first.
Tying up 8pts in the Skinwalkers seems like a lot to me at 15pts. I'd start with the smaller unit size and then expand to 5 for larger games.
Bast off of the list you posted I'd go something like...
Kromac (*4pts)
Warpwolf Stalker (10pts)
Argus or Gorax (4pts)
Skinwalkers (Leader & 2 grunts) (5pts)
Then by adding the below you would quickly be at 35pts.
Pureblood Warpwolf (9pts)
Expanding the Skinwalkers by 2 (8pts)
War wolf solo or Swamp Gobbers (1pt)
Or just play the models you like.
Cheers.
