Only 1 one-and-done on the UNC 2016-17 roster. Tony Bradley was 7 points, 5 rebounds per game. That was a largely veteran team. 2008-09 had no one-and-done guys.
Winning a Signing Period according to recruiting media does not usually result in a Championship. The methods used by recruiting media are hardly accurate and they end up driving a lot of the pressure to recruit particular guys and this results in the ballooning transfer rate independent of graduate transfers. Fit matters and the recruits, coaches and media fail to understand that. ESPN's hype machine in November will typically promote teams that will not reach the Final Four, they are driven by recruiting media hype and ratings. Analysts just say things because they have to say things and if they don't say something that is compelling or bold, they are not helping drive narratives that bring home the revenue. So that's a good tip for your NCAA Tournament bracket. Record ESPN College Hoops in November and watch the replay of everything in the studio that is said then to do a Process of Elimination on Selection Sunday.