#2 Improved efficiency in the midfielders

Guendouzi and Torreira are the signings of the season for Arsenal, as the duo has run riots in every game they played for the North London side. Their precision, timing and presence of mind are better than every other midfielder in their side.
Granit Xhaka's starting position was in doubt as Guendouzi and Torreira were outperforming him, however, they both are very unlikely to start together as Arsenal will lack some body strength in defending set-pieces.
The likes of Ramsey, Mkhitaryan, Iwobi etc have improved their game under Unai Emery as they look much confident than the seasons before.
The gaffer's game relies on pressing high and starting attacks from the backs, and this tactic demands high work rate from the players. Well, the Gunners have not disappointed their coach, either.