1.Connected Careers seems like a very in depth Head Coach 09 style mode, but with improvements.
2.Physics I shouldn't have to say much for this I think it speaks for itself.
3.Pass trajectory's has really made for a much more realistic and fun passing experience.
4.Presentation has really improved with a much better cast of commentary.
5.Quicker play action combined with being able to pull out of a play action animation.
Those would be my top 5 reasons to get this game. Obviously there is more to it and I probably missed a few points, but I think those reasons alone are plenty enough to warrant a buy for Madden 13.