It's a funny topic
I'm Italian, Celtics fan, and I know Gigi from many years. He is a very good shooters, has a high QI and play for the team. I think he isn't athletic enough and that made him a bad defender, but he is a great worker.
In Detroit he never has the opportunity, always stay out of the team's rotation. It's difficult, but I hope in Boston find that.
For me Gigi can stay in a bench of a NBA team but I don't think Ainge resign him.