I said before, I think the problem for AMN when he played across the middle for Wenger our midfield was weak. He didn't get that many games in the middle though.
According to Transfermarkt.co.uk he played in the middle for us under Wenger 3 times, one was a 4-1 win vs West Ham (he played with Ramsey and Xhaka), one was 2-1 loss to Man U, he played in a 2 with Xhaka and a 1-0 win against Huddersfield where he played in a 3 alongside Xhaka and Ramsey.
Some might say AMN in the middle doesn't make it stronger and I would agree with that, but he has proven to be adaptable, perhaps if he had a proper midfield general next to him his game would improve