Expected starting line-up
Unless Unai Emery has something different lined-up to counter-attack Manchester City's system it seems fairly obvious which team Arsenal will line-up with against the Citizens. This is my predicted line-up.
I think Emery has so far strengthened three of the positions Arsenal were weakest last season. Offensively, Arsenal are fantastic and can rely on the front three of Aubameyang, Mkhitaryan and Lacazette to damage any defence in the league. For years Arsenal fans have been crying out for a Patrick Vieira style midfielder and they've been given Mohamed Elneny and Francis Coquelin. They just weren't good enough for a side who were supposed to be challenging for the title.
Personally, I still believe Arsenal need another centre-back. I believe Sokratis will be an amazing signing for them but I'm still not convinced on Shkodran Mustafi and with Laurent Koscielny out until at least November an injury to Sokratis would mean Arsenal are left with Mustafi and Holding as their centre-back partnership - something I'm sure no Arsenal fan wants to see ever again.
In terms of a goalkeeper, it feels like it was the right time for Arsenal to move on from Petr Cech; it was great that the Czech international claimed his 200th clean sheet at the club but he realistically isn't at the level needed for a Champions League standard goalkeeper. He will definitely do a job at 90% of the clubs around Europe but the decision to sign Bernd Leno seems to be the right one. Who knows? It might even inspire Cech into recapturing his form.
The only position that should be strengthened is the left back position; neither Monreal or Kolasinac are strong enough defensively for a top four side.