Some seriously unfair grades here.
Chauncey Billups, Joe Johnson, and Len Bias were A+ picks given where they were taken and the talent they had and what they turned into or could have turned into. The scouting department of the Celtics, who you are criticizing, did their jobs with those picks.
As someone else said, Troy Bell and Dahntay Jones were traded for Perkins and Marcus Banks. Again, the scouting staff did their job here as I would say Jones and banks both were about the same in total career achievement and Perkins was a very good pick. Maybe a C- and a B for those two players respectively.
Jeff Green, Randy Foye, and Marchon Brooks weren't even picked by the Celtics for the Celtics. The Celtics picked them for other teams. green and Foye eventually turned into Ray Allen and Big Baby. Brooks turned into JJJ.
And it is inherently unfair to judge Melo based on not playing last year. He was developing, much like Perkins was developed his first year by not playing. If Melo is a rotation player in a couple years, then the C's made the right move by handling him the way they did this year.
And what about the success the C's have had in the second round with players like Ryan Gomes, Glen Davis, and Leon Powe to name a few? No credit for the scouting department there?