Sure, but they had to give up so much to get Ray Allen and Kevin Garnett, so that killed their depth outside of Paul Pierce.
Look at how many guys went to Boston at lower contracts just to play with them (James Posey, Eddie House, Sam Cassell, PJ Brown) for a chance to win. Doc hasn't figured out how to incorporate them into the lineup with Tony Allen, Rajon Rondo, Glen Davis, Leon Powe and Kendrick Perkins.
On paper, that looks like depth... Doc just doesn't have a good feel for the game or his players, particularly in-game adjustments. Look at game 4 - he needed to put Posey (a good defender) on a hot Joe Johnson and yet still stuck with Ray Allen, a below-average defender.