I'm not even sure Arsenal will return to the top of the table next season if their squad strength remains the same as last season and their style of play is more defensive than offensive. For now, I won't compare Arsenal to Manchester City because Arsenal just won the Premier League title last season. But with Arsenal's style of play last season, if it doesn't change immediately next season, Arsenal will likely be just a side in the top four, not a title contender.
Arsenal's performance at the champions league last season was not weak, they dominated the league's number first position, until the finals. Gameplay changes, nobody thought of this for Arsenal in the previous season that lead to the just finished champaign, the momentum and strength Arteta's boys gave out last season could depreciate or increase depending on the strength of the opposing teams.
If more teams come up with a strategy that deeply wounds the current or supposed tactical play of Arteta in the next season, he'd have no place there in the champions league top position, but if he outsmarts them then he'd get there more faster than usual.