So, I agree with moving on from him, but I'm not down on him as a player. As I've said before, this team has been put together with a painful lack of awareness about the league. We have one of the worst payrolls in the league given how entirely mediocre the team is. We've built a team that can't create shots and can't shoot even when they find open shots.
Moving Drummond isn't about him being a bad player, because I don't think he is. Being a truly elite rebounder has value, and he's at least shown the ability to defend (perhaps another coach could actually bring that out). If he wasn't such a train wreck from the free throw line, and scared to death of being fouled, I'm sure his offense would start making big strides as well. But he's just not going to figure that out here if he hasn't after all these years.
My favorite idea/hope is for Boston to fall out of the top 3. Boston nearly lost to Chicago because of their rebounding issues. Their big loss to the Wizard, unsurprisingly, came with a big deficit on the boards. Drummond would solve a big problem for Boston, and is certainly much more ready to contribute now than a rookie - keep in mind their best players are 27, 28, and 31 next year; they don't necessarily have a three year window to wait for that pick to make a leap. So that allows Boston to swap the 4th pick for Drummond (technically they could do this straight up if the salary cap comes in around projections, but it wouldn't hurt to take back Tyler Zeller to make the cap easier on them).
With the 4th pick we could take someone who fits a whole lot better and who still has some potential (unlike Stanley it would seem).