I don't buy Madden at all, but were I a Madden junkie I STILL wouldn't buy it on release date.
When you can consistently get the game at half price two months after release, and you still own the last game (released less than a year ago which has largely the same gameplay), buying Madden on release day, every year, just seems... inefficient. Just put in last year's Madden and play that for the two months you'd be waiting. There's no way that the improvements justify the cost.
Games released on a yearly basis that I DO enjoy, like Call of Duty, there's justification for the purchase. I just ignore the Treyarch ones so that I don't buy crappy reiterations every year. If I pick up the Infinity Ward ones on release date, there's a good chance that they'll stay at retail price for the entire year or more.
There's no way in hell Madden would do anything close to that.