I believe this is a symptom of a larger change in the Premier League, which many have yet to notice or appreciate. This change is that the talent gap has closed, not between the top and the bottom, where it is still a gulf, but between the top and the middle. Gone are the days when Arsenal can complete a season without losing a match, or Chelsea can lose only 1 match on their way to 92 points.
The big teams are dropping points this season, and I believe their are 2 reasons for this.
First, as I mentioned above, clubs such as Manchester City, Aston Villa, Tottenham, and even Everton have improved. Maybe not to the point where they are going to challenge for the title, not this year anyway, but to the point where they can take points off the likes of Manchester United and Chelsea far more frequently than they could 3 or 4 years ago.
Far more interesting is the second reason for this trend. This centers around the bottom of the table club's reaction to the strengthening of many formerly mid-table teams. In past years, a relegation threatened club expected little to no points from 8 matches against the so-called Big Four. The manager would put 10 men behind the ball in the away match and hope not to get embarrassed. And the home match wasn't very different, with the best case scenario often being a single point. This left another 30 matches from which to achieve the 40 or so points needed to stay up.
With the improvement of the other clubs I mentioned, managers of clubs such as Hull, Wigan, Bolton, Sunderland, etc., had a decision to make. They had to decide if they were able to sacrifice even more games, put even more importance on the matches against fellow strugglers. Some, such as McCarthy, Megson, Hart, chose this route. But many others went in the other direction. They decided to abandon the tactic of sacrificing matches, to actually try and win every game their club played. And it has completely changed the look of the league.
A lot more goals are being scored, a lot more end-to-end football is being played, and a lot more points are being dropped by the members of the big four. In fact, I would wager that Manchester United has seen more clubs play two strikers against them so far this season than in the previous 2 seasons combined. Now this tactic doesn't always work, we have seen some struggling clubs try to attack the big sides and get embarrassed 4-1, 5-0, 6-2, even 9-1 on 1 occasion.
Personally, I like this change. This newfound ambition can only be good for a league that had become all too predictable the last few years.