Yes, it's very true that arsenal are in a very good run of form right now, and it will be very difficult for them to lose a point between now and the end of the season no doubt, but their remaining fixtures compared to the fixtures of Manchester city is actually really troubling, because they still have Manchester united to play, a team that haven't been doing well no doubt, but they mostly step up against the bigger teams, and if you look at their head too head record against Manchester united, you will actually know why almost all reasonable arsenal fan would be worried, because that's a game that might end their title dream if care is not taken.
And as for Manchester city, I have said this before, and am still going to say it again, the biggest mistake made by both arsenal and Liverpool was allowing Manchester city go above them in the league table, because the Manchester city I know have the ability of winning all the remaining fixture and be crown champions at the end of the season, and one interesting fact about them is that they always wins the league anytime they go top, at this stage of the season, because they would not let any slip up again.
with Arsenal's good performance this can make them at the top of the rankings, but the points they have are still not safe, Manchester City is still a threat to Aarsenal, because with their narrow points difference it could allow Manchester City to overtake their points and returned to its top ranking. Also I think with Manchester City's next match that will take place I think they can still catch up with their points which are slightly different from Arsenal so there is a possibility that Manchester City can overtake Arsenal.
Of course, Manchester City's performance cannot be underestimated, Arsenal must be prepared for their ranking which might be shifted by Manchester City, which is performing well.