That's the same way the Gunners performed last season and we all thought they were going to be the new champions after a long period of time but they failed themselves and the fans as well, even though they are with a very high number of goals being scored I still don't give them that 100% assurance that they're going to win it without any upset, until they get their cool together I don't think they can win the league without some of us thinking otherwise.
However, Arsenal performance this season is more stable, they could play more consistent. It was different from Arsenal performance in the last season, they become a more established team in this season. Personally, I think Arsenal have changed, their chance to win EPL also should be higher now. Sure, there is no 100% guarantee for the title, it is something impossible. But another good factor that Man City is no longer as strong as the last season although there is Liverpool as another competitor for the title.
And Arsenal are not a team you'd put all hope on that they can get things done after failing in different occasions, they're suppose to win the Europa league against Chelsea but they didn't, they're suppose to win the league last season but City got it, so they are never a team to rely on until they get the job done.
The result on Europa League can't determine the winning chance in EPL. I think Arsenal has been a different team now, they are in a better level. If they play against Chelsea, they can destroy Chelsea. It is different with Man City, they even drop their performance in this season. So, people can't expect the same way of Man City to win the title race like the last season.