Could be Nesmith (plus someone else)? And we just play smaller...?
After all the success we have had with our two-big line up, you want to build the team around a line up with a 6'-5" wing, who is not all that good, as your PF? I would rather just go with Grant Williams in that case.
I am going to be very surprised if we need to replace Al Horford for next season. It seems almost certain that he will come back and I don't expect him to be all that much different at age 36 than he has been at age 35. Unless something unexcepted falls into our lap, I doubt we do anything this off season in terms of replacing Al.
I look at someone like Marvin Bagley. Now I don't think we are going to have any shot at him specifically at this point, he will likely now sign with the Pistons, but we should be on the look out for a player like him, under performing in a bad situation, and say at the trade deadline next season, take a chance on someone like that. Al buys us time to allow us to be patient.