Short answer: ZX10 in its current state, yes. PanigaleR in its current state, yes. RSV4 in its current state, no.
We are simply speculating, right? So here is the extended version of my answer:
Good questions Migs. As a Rossi fan, I think you can appreciate the effect it might have on a rider who has been cruising around on inferior machinery. Rossi, the greatest of all time, wasn't able to win straight away when Carmelo cleared the path for his return to the factory M1, which entitles the rider to a 1 in 4 championship contending machine. Consider that he was only gone from the M1 for 2 years. Let's shelve VR's performance on the Ducati (which was a machine that had won races and scored podiums the previous year) as you are probably well aware, Heisman, Gaz, Michaelm, JPLotus, AntG, Kesh and others completely rehashed that episode, no need for us to repeat here. But consider that Rossi's performance was dismal on his return to a machine (M1) that was an absolute contender in 2013.
In GP, as opposed to WSBK, the parity picture is fairly straight forward, the 2 factory Yamahas and Hondas are the championship machines, if you are on one of those, you got a 1:4 chance of winning the title, period. The odds get better when 1 of those 4 riders has problems, as you see today, its basically a 1:2 deal, not dissimilar to what happened in 2013 when both Lorenzo and Pedrosa broke their clavicles, at which point you would have thought VR would have come in a comfortable runner-up, which did not happen. To support the idea that the M1 was a title contending machine, Lorenzo came within 5 points of winning on it in 2013, the same bike Valentino (the standard of awesome) simultaneously rode. Valentino Rossi, again the greatest of all time, wasn't able to win the title in 2014 either, while of course riding on a title contending bike with the odds being 1:4. I'm reminding you of these facts to build a case that even you could appreciate the difficulty an excellent rider such as Nicky might experience to win a title straight away in WSBK; if even the absolute standard of greatness (VR) has experienced difficulty, which let's be honest, you are asking in such a way to present your peculiar opinion of Nicky, which I'm ok with, but I'm just using your guy as a parallel, you still with me?
The parity picture is far less clear in WSBK, unlike GP, because it ebbs and flows with less predictability. From Ducati to Honda, to Suzuki to Kawasaki to Aprillia and even BMW at one point trade parity not just any given season, but even within/during the season. Not just the factory efforts, but so to the satellites/privateer teams as you may recall with Athea Ducati, dominating over Xerox Ducati with Checa, and Ten Kate with Hannspree verses Ten Kate with Pata were far different animals as opposed to the Castro Honda days.
So, I do think Nicky could win a title in WSBK, but that would be assuming a healthy Nicky on a contending machine. If not on the first year aboard a ZX-10 (as it sits currently at the top of the parity table), then certainly in a couple of years getting to grips with a RSV4 or PanigaleR. Notwithstanding Arrabi's smug grin as I'm imagining it, Jrea is probably the best rider at the moment, not just because he is on the best bike, but in reference to his performance on the Pata CBR1K. I don't believe (yes I concede bias opinion) that Chaz, Sykes, nor Haslam are better talented riders than Nicky Hayden. Think in your minds eye, would these fellas fair any better on the RCV-RS than Nicky is doing now? By the same token, I don't see Nicky fairing much worse than these blokes on their respective machines after a year in WSBK. Again, lots of factors to consider, confidence, experience, health, familiarity, etc. Just so you know, I consider Haslam to be a top rider, and he's proved it despite being beat by Melandri and JRead while on same machinery, but you see him there today on a decent RSV4 contending for podiums and wins. Do you think he is a better rider than Hayden? How about Chaz or Sykes? I just don't see it Migs.
Again, all just speculation. But I'll finish by saying this, Nicky never said publicly that he would even consider WSBK up until a few years ago. So his heart is in GP, even on a .... machine. I asked him the this very question at a Ducati meet and greet, and it was the first time I had ever heard him be open to a SBK stint. At this point as LeviG said, it might be too late. The damage has already been done to body, confidence, prestige, marketability, age, etc.