Found this forum via a google search of NBA2K10 ratings. Those are my ratings, not 2K's. I've been editing ratings since 2K3 and I've built up a following. You can find the bulk of my work on gamefaqs.com though I decided to switch to blog format this season.
2K overrated the majority of the star players. Roy and Aldridge were not exempt from this. So it's not about them "getting worse", just being accurately rated.
Roy's block/steal ratings were much too high. Aldridge's block/rebound ratings were much too high. Aldridge's offensive rebounding was so high it was significantly better than Greg Oden's, which we all know is simply not true.