I've got to say I quite like Volkraken. I think it's getting a lot of flack because it isn't a one-mon win condition (as compared to, say Cawmodore), but it's important to keep in mind the initial concept when evaluating. The fact of the matter is, while the originally intended core of Luke/Latias/Volkraken isn't quite up to snuff, Volkraken was designed from the beginning not as a team-sweeping behemoth but as a role-player, able to slot into a team and provide valuable support to its teammates. It shouldn't be able to crush everything or outspeed everything or set up and win games on its own. It's designed (quite explicitly) to play a role in a core, and for that purpose I think it's fantastic.
It's also important to keep in mind the inherent flaws of a playtest ladder: people are overpreparing like crazy for Volkraken, which presents a frankly diminished view of its viability. I think if the meta had more time to stabilize we could see a better picture of what Volkraken's strengths and weaknesses truly are.
I've been using a Scarf/Analytic set for the most part, and in my experience it puts in good work. It works as kind of a Pseudo-trapper; you come in to revenge, and your opponent either losses the 'mon or takes a VERY big Overheat to the face. Obviously, hazard control is crucial, but unless your opponent has a dedicated Volkraken counter in the wings, something's getting messed up (mind you, most people have two - see above). There are probably scarfers out there in a better speed tier, sure, but in terms of pure damage Volkraken is out in front. It also helps to pair it up with something that eats its counters for breakfast. While it may be hyper-specialized, I've been running a two-scarfer team pairing Volkraken with Kyurem-B and the offensive synergy is GREAT (but, to reiterate- hazard control, super crucial).
Overall, though, the question with CAP is, as always, did we fulfill the concept? I'd say you can make an argument in either direction. I think Volkraken is a valuable mon that plays well with a number of partners - I myself am again fond of Kyurem-B. But did we, from top to bottom, design a viable and competitive core based on Volkraken and our two chosen 'mons? No.
The take away from all of this (and from CAP history, I'm looking at you Voodom) - designing cores from the bottom up is HARD. It requires a lot of natural chemistry, and more than a little dumb luck.