The problem is we probably never will know the true story about George, so faulting the Celtics on that is based on speculation. We've heard that other teams had better offers on the table than what Indiana ultimately ended up taking, so perhaps Pritchard wasn't just automatically taking the "best offer," the best being subjective of course. Some theorized that Pritchard (or the owner, you can never discount the owner's meddling in these cases) let it become personal. George had told the organization that he was on board with staying during the season, then changed his tune at the end and announced publicly he wasn't returning, destroying their leverage. That probably didn't go over too well with Pacers management.
Pritchard came out recently and said all those rumored offers never actually existed, but that is suspect too. The organization and especially him took a lot of criticism for not getting enough in return, so claiming a lot of the leaked trade offers were actually false makes the deal they DID make look a little better. Actually, I take that back. Keeping him and losing him for nothing would have been freakin' better than what they got!
The other half of the criticism is choosing Tatum over Fultz and I can definitely understand that. If the writer believes, as most scouting reports did, that Fultz is a superstar and Tatum is just a good starter/occasional all-star then Ainge definitely deserves a C grade just for that. We won't get the full picture on that trade until the Lakers/Sac pick is conveyed though, so this is another one that will take a long time to judge.
To be honest, I'm not sure George + Hayward was ever a realistic plan. How were the Celtics going to pay BOTH George and Thomas? You'd never be able to convince George and Thomas to take discounts because you've got Horford and Hayward making 30/year. Would the Celtics owners really be willing to pay 120/year on four players? Add in all the other guys and you're talking about a crazy tax bill, and the team STILL might not be favored to win the title.