You can definitely finish outside of the top 4. Its not exactly unrealistic scenario, the competition is just that strong this season.
There's no doubt in my mind that City have better squad, at least on paper.
Chelsea have Mourinho who's always challenging for the titles.
Arsenal are finally looking like serious contender, at least if they manage to stay injury free.
Spurs brought fuckzillion of players and they can only get better once AVB has some time to work with the squad.
And Liverpool are second in the table even playing without Suarez.
Lets be honest here, you're 3 points behind top 6 right now and all the teams i mentioned are going to score points pretty consistently throughout the season. United better start improving , and fast.