I disagree to be honest, I would have agreed with you a few years ago but the Arteta of last season was doing as much defensive work as Phil Neville and he revelled in the role.
Watch him closely once he gets back to his best, his positioning is excellent, similar to Xabi Alonso. And he was showing tenacity and putting his foot in when required. He's a very disiplined player, probably too disiplined considering his qualities going forward.
He played the role without Neville against both Spurs and Manchester City and we kept clean sheets in both games, he was excellent, our standout player. He carried Castillo against Manchester City and held whilst Fellaini and Cahill attacked against Spurs. After Neville he's certainly our best and most reliable defensive midfielder.
Hopefully he does get back to his best, it's going to take a while though. I'm still gutted we missed out on Ever Banega, who's doing very well for Valencia I might add.