Tons of people: analysts and fans alike. Which is stupid. One injury-plagued season doesn't wipe away 316 wins and the second-best record in the NBA since 2009 (behind the Spurs).
Yeah, I have to say that it's hard to feel too positive about a team expecting significant contributions to a playoff run from Enes Kanter and Dion Waiters, but it's hard to doubt Westbrook, Durant, and Ibaka.
Those three, plus handful of decent role players in Augustin, Morrow, Singler, Adams and Collison should be more than enough for 55ish wins, provided the core three stay healthy.