Really hasn't been a winger in pole position entering the year since Yakupov and previously Hall. Generally, the person in pole position holds on such as Dahlin, Matthews, McDavid, MacKinnon (but that was more of a split with Jones), Tavares, and Stamkos. Now, you see the occasional pass by an underdog like Hischier. 2014 was really a split to start the year between Ekblad, Nylander and Reinhart. 2011 Larsson probably had the lead to start but RNH entered the year pretty much top 5.
I get your point that bad teams generally desperately need a center, and therefore will take one which is why Byfield is a threat. But, it could also play out like Hall/Seguin, where the real tie-breaker ends up being a track record. Hall had 3 elite seasons to fall back on as a late-birthday, Seguin had a very good OHL rookie year and an elite 2nd year.
I'm not sure teams prefer defenders over wingers. Defenders tend to have the most uncertainty outside of goalies and the riskiest projections, whereas wingers tend to have the safest (although, there will always be Yakupov's). 2014 was wide open at the top, and Dahlin was a better prospect than Svechnikov. High-up in the draft we've seen guys like Marner go over Hanifin who were viewed as in the same tier, Drouin over Seth Jones, and we've seen the reverse with Juolevi over Tkachuk.