That is, we were constantly losing guys who were counted on to be numbers 6-9 in the rotation. Powe got injured. Scal got injured. Shaq and JO were brought in to give Perkins time to heal -- only they got injured. Delonte' was brought back to provide depth (and rest) behind Rondo -- only he got injured and missed most of a year. Big Baby stupidly hurt his hand punching some dude. Semih Erden played well off the bench ... and got injured. Marquis was brought in to provide depth behind Pierce -- and got injured. Nate got injured. Krstic came over in the Perkins trade and played well - then got injured. Then we lost him to Russia during the stupid lockout. Jeff Green and Chris Wilcox each had to have their chest's ripped open and their hearts operated on!!! Stiemsma emerged as rotation big supporting KG -- and got injured. Bradley emerges in the second half of his 2nd year as a legit rotation/starter -- and gets injured. Barbosa. Pietrus.
Some of these were expected, put out a team of old guys and this is what you get on some of the veterans.
Still, may Ray has been there too long and we need a new trainer.
I agree, some of those injuries could have been predicted (Shaq, J O'Neal. Or, the player was so old he slowed down by the end of the season and couldn't give useful minutes (Shaq again, Sheed come to mind).
As far as the other names you mentioned go, those guys were never that good to begin with. Some of them weren't even in the league a few years later, so how good could they have been? Daniels was a bust even when healthy. Stiemsma, Erden, Scal, and Wilcox are not guys I would really call difference-makers. Courtney Lee, Jason Terry, both disappointments and given 4-5 million/year contracts. Nate Robinson was a bright spot though.
Also, if you draft a guy who turns out to be a head case (West, Davis) you certainly deserve some blame for that.
Finally, Green was healthy the year of the trade. He didn't lessen the load on Pierce that year and didn't when he came back either. Ainge will defend him publicly but I'm sure when he gave Green that contract he was expecting a little more than what he's gotten so far.
The David West deal would have been huge but Ainge couldn't get it done. Finding a way to convince Tony Allen to stay was also important.
If you were going to defend Ainge on the bench construction I wouldn't use injuries first, rather I would blame the difficulty getting good players on discounts due to the perception the team was past its prime a few years in. That's the problem when your window is so small. Players were not falling over themselves to come here like they are for LeBron.