Ainge is fine, lol. I think he's done a hell of a job putting this team together. He's not infallible - no GM is - but he's way beyond the 'fire him' benchmark by my estimation.
I disagree that he didn't pick a direction. Kyrie/Brown/Hayward/Tatum/Horford/Smart was his direction. But Kyrie leaves Earth, Hayward breaks his foot off, Horford leaves for more money, and here we are. Ainge didn't do anything wrong. But the reality is that you need to get lucky, in addition to making savvy moves, to win championships.