Sometimes, when a new, especially young, coach comes in, you have to clean house. Some players won't play for new coaches if they were spoiled with the old regime. It looks like DA is cleaning house and will build through the draft, and then try to make a splash with a legitimate trade, but that won't be this year.
I think you can build around Smart. He has the tools, and they're obviously making him do things he's never done in order to become a complete player. Watching him in College, he's always penetrated the basket where ever he's gone, yet he refuses to do it. I don't think coach wants him too.
So in the next 2 years, you will see things come together and the Celtics compete for a C, but you had to clean out the old baggage who would not buy in to the system.