I actually tried stretching out the ratings in 09 quite a bit and it really seemed to improve gameplay. I haven't tried it with 10 yet, would have if you could edit ratings in franchise to adjust progression to make up for the greater spread in ratings and also be able to edit incoming rookies so they weren't all way stronger than the rest of the league as they wouldn't be spread out.
As for the rest of what you said, I agree. Nearly all the ratings are needed and they really need to add more to differentiate other areas but only after they fix their programming to allow ratings to have more effect on gameplay.