So glad you brought this up. I believe I was actually the one who brought this to the attention of the OS community. Of course, some people still try to defend the whole aspect of it.
But like others said after you, if practice is handled nearly the same way within a couple years all teams would have highly rated players. Hopefully with them going towards drill type practices maybe they are focusing on you only being able to earn xp to only a few players per week (whoever you use in the drill). That would be a far improved system.
I personally would rather see them do away with the entire xp system. It was an interesting concept, but it just doesn't work right. CPU teams do not know how to utilize it and it is also unrealistic to be able to make these types of improvements to veteran players. They just need to have some sort of system where players make most of their improvements their first couple of years in the league (so basically throughout their rookie contract). And then in rare occasions have players improve a little bit more down the road to mimic those types of players who don't really hit their prime until a little bit later in their career.
They also would need to make progression only slightly affected by statistics at the end of the year. Some people think it should be based off of player performance but I don't agree with that. You can use Vince Young as an example. After some of the things he was able to do in his rookie year I think many expected him to become a star in the league. What happened instead was he had a sophomore slump and was never able to come into form. So even though he had a solid rookie year with some great comeback wins he never panned out and now he is unemployed.
In that sense I would like to actually see players able to regress earlier on in their careers. Maybe somebody has a big year the final year on their rookie contract and signs a big contract in FA. Then their overall ends up dropping off a bit. Players often have big years but then fall off the map. As a Dallas fan I can think of two such players. Roy Williams and Roy Williams. The safety used to be a force in the middle and the WR at least had 1 big year in Detroit and two respectable ones before going to Dallas. Both continued to decline in play well before you could blame it on their ages. Another person that comes to mind is Albert Haynesworth after leaving the Titans. Anyway, even though I would like to see this I feel it would turn off to many gamers as they wouldn't like a player that they were expecting to be their star regress after a good year statistically.
I personally would like to see the training camp from way back when come back in some aspect. For those who didn't play back on xbox and PS2, they used to have minigames (drills) for training camp that you would run a player through. They had like 8 or so of them pertaining to different positions (for some reason they had 2 QB ones while only having one for DBs and whatnot). You could only run one player through the drill and, depending on how you did, got somewhere between 1-7 points to add to the players attributes (it was restricted to only certain attributes, so you couldn't boost speed by 7 or anything like that)
Anyway, I'm starting to get off course. I won't be able to bring myself to buy madden again until they fix the way CPU teams handle player personnel. Teams allow their franchise QBs to walk in free agency far too often and I just can't take how unbelievably unrealistic it is