If it gets more "realistic" in the manner it did this year, adding more accesories and slowing down the game a little and making other such small changes, then yeah it won't drive people off.
However, casual gamers tend to want to be able to win with their favorite team regardless of what that team is. most online gamers and tourney gamers and anyone else who doesn't fit into that real "sim" group wants their stick skills to overpower ratings. Really, pretty much every other than franchise players and a few others would rather not have ratings be the major distinguishing factor. Even on this site with such a high concentration of sim gamers as we have there have still been arguements on here as to whether or not ratings should overpower stick skills. While I agree that ratings need to matter more how often do you see someone on here say that their quarterback should never randomly make a bad throw just because of ratings when they "used their stick skills to make a perfect pass" which apparently takes way more than just pushing some button.