Agree on JaJuan, but we knew from the beginning that Melo was going to take several years to develop. He wasn't going to help us this year, and he probably won't help us next year either. He's the definition of 'long-term project'. Too early to call him a bust.
'Last three first-rounders' is also a very convenient stopping point for your argument, given that he drafted Avery Bradley with the pick before that.
It's also worth noting that the 2011 draft sucked after the first pick. Danny missed on JaJuan Johnson, but very few guys drafted after him have done anything. Chandler Parsons is good, Jimmy Butler is looking like a very nice prospect, Isaiah Thomas has played well for the Kings and Norris Cole is a serviceable backup guard, but the list basically ends there.
All in all, I wouldn't read too far into it at this point.