I'm not sure how would all those SPN fans worldwide react if Wincest would be made canon. + The censors would never allow it in the first place, so I'll go with ...

Neither really.

I don't think either would be made canon. But I think there's a slight more possibility for Destiel, and if it did happen I'd be disappointed, because it would be so obviously pandering to those fans instead of a more true/natural development of the story.

Wincest is canon in my book. You guys just don't see that. Destiel's no match for Wincest. Wtf cares about the censors?! It's a fandom! We're living in a free country. W\incest is not the worst thing it could happen to SPN. Let's face it. What do we got here? 2 brothers who fuck each other, and we have a man who's fucking some bloody angel. So, which one do you think is more likely to become canon? Wincest! No doubt about it.

Most definitely Destiel. It's already half-canon anyway.