Looking at the list of former Wizards, I don't feel too bad. You've got 2 of the worst 5 contracts  in the league on the list (Ben Wallace and Larry Hughes), the biggest  #1 draft bust ever, and a couple of past their prime former stars (Stackhouse, Webber, and Howard). Steve  Blake left because he knew that he'd never get good minutes as Gilbert's backup, so not much we could have done there.
We have missed Dixon's scoring off of the bench for the past 2 years and only now are we coming close to replacing that firepower. Trading Hamilton was a mistake but at least we eventually got Jamison for Stackhouse and a first round pick. I've never felt bad about trading Rasheed Wallace for Strickland. At the time we already 2 good power forwards and needed a point guard to take us to the next level. Strickland gave us 3 good  years. Also remember that Portland ended up dumping 'sheed in a midseason trade when they grew tired of his act. Only then did he become a "championship" caliber player. So all in all, I don't think the Wizards have been that awful with their moves over the last 10 years and have done pretty well recovering from their mistakes (getting Jamison and Butler).