Otis Smith, who decided to blow up a contender for no good reason.
When you have a team as close as Orlando was, you add to it, rather than destroying it. Gilbert Arenas wasn't a good gamble at the time, and nothing about his play has changed my thinking on that one.
I agree that Otis Smith is to blame, however I don't blame him for making a trade. I believe the trade was a side step, not a step forward. They upgraded by taking back Hedo, basically got a wash with swapping VC for Richardson, lost depth at C by letting Gortat go, and got a wash for letting go of Rashard Lewis and giving Ryan Anderson minutes.
They were not going to advance any further with who they had before the trade, and because they only tweaked their time instead of really improving it, they are out again. A trade was needed to be a legit contender, it just may not have been the right one. At least Smith didn't wait till the trade deadline to initiate the change, giving the team time to come together.
His comments in regards to the Heat and Celtics shortly after the trade made me feel like he either didn't really have a true concept of reality about where his team was compared to the other elite teams in the league, or he was just simply a bit classless. He made some punk statements for a gm.