I'm with Larksea on this one, Mils is good at 13, but there's a reason he's the best full back in the world. His angles, the way he reads the game...and he's getting older now, why isn't getting slower?
I swear the guy is a machine.
I can certainly see the argument against moving one of the best fullback in the world out of position, however the advantages of playing him at centre (just) outweigh these negatives in my opinion. There are two main reasons I'd consider moving him to centre until Kahui comes back (if I was coaching the Chiefs - as an AB supporter I, like Larksea, don't want to see him in a 13 jersey....) :
1. Nanai-Williams gets to start in his favoured position of fullback. Nanai-Williams was the Chiefs best attacking option during the latter half of last year (starting at fullback while Muliaina injured), and was the most dangerous Chiefs player on the park last week. Sure he does make the odd mistake and does have a few defensive issues, but he is improving in these areas. He really is a freakish talent, it seems a real shame not to be giving him 80 mins every week.
2. It will greatly strengthen the mid-field. With the likes of Sivivatu, Masaga, and Nanai-Williams in the back three all the midfield have to do is give them the ball - Muliaina will know exactly what to do (unlike Sweeney who is bound to cut back every time he gets the ball). Likewise he would certainly strengthen their questionably midfield defense.
As a supporter of the Mighty Southland Highlanders I feel much more comfortably facing a backline of Kerr-Barlow, Delany, Sivivatu, Sweeney, Willison, Masaga, Muliaina than I would facing a backline of Kerr-Barlow, Delany, Sivivatu, Donald, Muliaina, Masaga, Nanai-Williams...