Presti's first bad move? Or will it end up being the second after Green blows up this year, and Melo develops down the line? 
Are you joking?
Melo is going to be playing more in the D-League this year than the NBA. Perry Jones III looks a lot more ready and he's coming into an ideal situation where he can learn behind Durant.
Green hardly even played last year, due to a heart condition, so I have no idea where your expectations of him 'blowing up' come from.
Harden to the Rockets had to happen because of cap reasons. Harden wanted max salary and Thunder could only offer 54m before running into the cap. I believe that in addition to Martin and Lamb, the Thunder will receive 2 1st round picks, one of them being a lottery pick.
It's a shame that the Thunder had to break up a dominant offensive trio of Durant/Harden/Westbrook but they got some decent compensation and if they draft well might yet find a 3rd star.
I see Kevin Martin as more of an expiring salary/trade chip to use at the trade deadline. He'll be somewhat useful but the Thunder are not going to keep him long term. Lamb, I have no idea what he will turn into but I don't think he's expected to be an all-star or anything like that.
JJJ isn't an NBA player, as Houston learned rather quickly. Him being cut should tip the Brooks/JJJ debate Marshon's way for most reasonably thinking fans.
True, Brooks looks like the better player than JJJ. But JJJ did lead to a package that landed us Courtney Lee. So the question then becomes is Brooks better than Lee? That's still debateable until we see more from both.