First of all, the statement that we know what we got is trash is flatly untrue. We don't know how good Lamb will be in a bench role, and we haven't even selected a player with the Raps pick yet. Sure, it's not an equal value for what we got for Harden, but what would be?
As I said, I would have preferred Beal or Klay Thompson, and GS and the Wiz were stupid for turning down the offer of Harden. Presti clearly took what he thought the best deal was, even if Harden's value was decreased because of his pending free agency.
As for your suggestion that we should have completely blown up what turned into a 60-win team by getting rid of Westbrook "and/or" Ibaka... I'm not sure what to say. YNB is a top 10 player already and improving, and you have to have quality bigs to win. When's the last time a team chipped without a quality PF/C? Also, (as shown by the Harden trade) getting equal value in trades for players like Westbrook is virtually impossible. Ainge called Presti and offered Rondo, FFS.
We still had a decent shot at the Finals this year if YNB had been healthy. Presti's goal was to maintain quality, sustainability, and flexibility into the future, and he did that. I still don't like the trade, but quit acting like Presti is a dumbass.
By far his biggest misstep has been retaining Brooks as coach, but our roster is still championship-caliber.