I think a big part of AD's form this year, his extension, the general morale of the side etc is that he's been backed for the role he wanted in the halves instead of having to train in multiple positions in the offseason because he was going to be moved around all the time.
Ultimately you have to do what's best for the team, but moving him to lock or especially centre when he's been playing so well and has only trained in in a ballplaying role all offseason would be a big call with impacts beyond just what we can jot down on paper.
We've got another three weeks or so of the AD/Madden combination to see how they both go, but if AD keeps playing well I think Madden will just get benched, right call in a vacuum or not.