I don't think that this season would be like last season for Arsenal, because they have the quality to keep on winning their matches and finish on first position on the table. I believe that Arteta have learnt from last season, and he is very cautious of himself now to prevent last season from repeating itself again.
Arsenal is better this season that they were last season, but it doesn't mean what happened can't happen this season. All that needs to happen for them to fumble the league is to drop point and both Man City and Liverpool drops point. Arsenal still have tough matches to play and those matches can determine a lot. Winning seven games in a row with the kind of pressure teams have towards the end of the season is no easy task.
Assuming it is City that is on top, I don't think that any club can take it from them.
If City was at the top of the season by this point of the season they'll definitely win it. Manchester don't joke around with opportunities like that. The mistake Man City made was not winning Arsenal and Liverpool in the second leg. I doubt Manchester City would drop points again, so they'll be hoping both teams drop points.