I did a couple charts in Excel based off of the IGN guy's sim stats. Just a visual representation for those who aren't impressed by the raw numbers.
The first one isn't too impactful at a glance, but if you compare 2010's line (dark blue) to 2014's (purple) you can see that 2010 is more or less a bell curve, with not a lot of teams at either extreme end (just one A+ and no D- teams). The curve shifts over each year until we get to 2014. What looks to be happening there is basically that the high end is now B+/A-, not A+ (there are zero A+ and A teams); the meat of the curve has drastically moved to the C and D range; and the bottom end of the curve disappears into a glut of D- teams, because EA doesn't rate below that. Presumably if there were F+, F, and F- ratings, the curve might taper off a little more.
The second one has been simplified (each letter grade consolidated, though I kept D- separated from the D+/D aggregate to focus on the increase in the worst possible rated teams). It shows the radical dropoff in A and B teams, the somewhat less but still noticeable increase in C and D teams, and the extreme increase in D- teams.