What's cool about hiding the ratings and showing "traits" is that just because two players share the same trait, does not mean they have the exact same level of ability. I thought APF did this perfectly and this could certainly be expanded. Also, when it comes to XP - I'm not a huge fan of it, but it can be tweaked to be more realistic. The use of XP is not necessarily complete nonsense. It's how you EARN the XP that is completely stupid. Let's face it, do players in real life really get better by simply performing better? They get better through practice habits and off-season dedication, coaching, opportunities to play, etc. etc. You could tie XP into players' work ethic, natural ability, etc. For example, certain players should have a cap of how good they can get. Bill Bates was never going to be as good as Darren Woodson, no matter how much he played, worked or dedicated himself in the offseason. XP is too easy to gain and it's MOSTLY universal for every player. Randomly, certain players are given the slow, normal or development trait. However, even with slow dev, I can still turn Prince Amukumara into Darrell Revis in a season. After 2 seasons of CFM, everyone has ridiculous corners and linebackers. Offensive lineman are all in the 90s for blocking, QBs like John Skelton are superstars similar to Peyton Manning and Tom Brady. It's silly.
How about taking a look at what guys do in the offseason and build in game models of those things. Allow you to create offseason regimens for your players. Specify focus areas for guys related to their positions and their weaknesses. Have Vick Study more film and work on reading coverages. Have Greg Little spend x amount of hours working on drills to improve his hands. Have your coordinators spend time studying game film. After the offseason, guys can accumulate some XP based on the areas that they worked on, and that xp can be applied to improving their attributes in those areas. This will lessen the extreme mass building of players all around, and be a much more realistic representation of how players actually improve and progress. You can go further and have risk and reward. For example, if you have a guy working hard in the weight room to improve his strength, you can have different levels of intensity or more workouts which can potentially result in more XP, but will increase the risk of an injury. Speaking of injuries, when a guy gets hurt, how about having the option to increase rehab frequency or intensity. Risk is chance for setback, reward is faster recovery and a return to the field.
Nothing I mentioned here is overly complex or invented in any way. It is using the model of the real life NFL that is available to anyone to see. I believe these types of things could be done and they could be done very well.