Why not amend the Constitution to allow Presidents to serve any number of terms — but no more than two consecutive ones?
Not only would this make Bill Clinton a possible candidate again, but it would keep the virtues of the current term-limit rule — forcing a degree of regime change — while reducing both of the worst effects of lame-duck status: the pointless Presidency and the lack of constraint on politicians who know they need never face the voters again.
Not that it would do any good with the current office-holder, who is a lame duck no matter what as the electorate has (finally) soured on him, but you can’t have everything. (The cure to the current problem is already found in the Constitution.)