Well, due to the Memory Card constraints, I doubt that it will be 100% up to Ps2's level. But the changes are yet unknown, and possibly, they will be less noticable than the changes from Madden 2002 (Ps2) to Madden 2002 (GCN)
On that game it just cut back on created players, and that alone saved masses on memory (instead of being able to create 200 players, it was limited at somewhere below 100). It also lost generated rookies... instead the rookies were saved to the disk before-hand.
But this time it's isn't going to be THAT bad, because that was 500kb to save a 2500kb game... now that there are Memory Card 251s out it will be 2,000-2,500kb to save a 3,500kb game. so the cut-backs shouldn't be huge, but it will take your whole card sadly
Changes that will be good:
1) Better sound and better graphics
2) If it's like Madden, it will beat the Ps2 version in AI also