It was always silly to sell him after a major injury but there were a lot of knee-jerk reactions to a mid-table squad and he was one of the underperformers. Not that he was playing well enough at the time, but you don’t sell low. It seems like that attitude has changed, but it’s also coming off two trophy wins. Wait until there are some losses again, those opinions will start coming right back.
I like Bellerin at right back and AMN at left, as long as Arteta keeps playing Tierney as left center back. But once some of those left sided center backs start coming back – Magalhaes and Mari – then one of the three (including Tierney) is surplus to requirements. AMN is not at the level as a midfielder. It’s a bummer to have to consider getting rid of one of them but there are too many holes elsewhere to have surplus good players like that (or at GK). If the squad was in good shape then you keep all of them but there is a need for 2-3 starting caliber central midfielders at the moment. So Arteta unfortunately does need to sell one of them and fill holes elsewhere. Plus, it seems like Arteta would prefer 4 at the back, but he doesn’t have enough midfielders to play that formation.