Arenas is making big bucks, not sure of the total, but it is close to 100 million. It is possible that is the worst contract. At the same time Arenas is only 27 right now, and he will be only 32 when the contract ends. So he is entering his prime. I don't believe he was a max contract guy to begin with, but if you are going to pay max money you want it for the peak years. There have been a lot of other players nowhere near as good, who signed contracts for similar money, and were older. With two injury riddled years behind him, and if that is the future then this is clearly the worst contract out there. If on the other hand he progresses like a 25 year old with his stats typically does from 28-32 then it is far from the worst contract out there.
Washington is off to a poor start. I still believe that once they get everyone healthy they will be one of the top 4-5 teams in the east.