I really like what you have to say Valdarez, so please don't take this as an attack, but you are unimformed here. 2k uses ratings just like everyone else, but in 2k8 they are hidden. The attributes are ratings boosts that your players have.
Generic players you choose from have three default ranges. For receivers you have deep threts, balanced and possession. Deep threats get a bonus to speed while they take a hit in their catch rating(s), balanced players have an even balacne between speed and catch ratings but aren't great at either rating and get an improvement to route running while possession receivers get a bonus to their catch rating while they take a dip in speed. The same is applied to all other positions.
For Bronze, Silver and Gold players, they get skill boosts. If you give a player speed burner they will get a bonus to their default speed rating, Ball hawks get a bonus to thier catch rating and minor coverage boosts, etc.
2k8 is polished 2k5 visually with the NFL stripped away and additional in-game presentation. The animations and ratings still work very much the same. they didn't get rid of their 2k5 ratings, they just wrote generic ratings for each position and you pick what kind of bonus and weakness you want the game to apply to your players when you pick generic guys or create your own players.
Numbers are how programs work. It doesn't matter what the game is. For example, Call of Duty Games have hidden numbers regarding how fast you can walk, run, crawl, jump, accuracy, how much health you have, how much damage bullets do, etc. etc. etc. You get to see a bar graph of the weapons strengths and weaknesses, but they are still nuimbers driven. It is no different when playing a sports game. the game has to know how fast to set an offensive linemen, a full back, a power back, a speed back, a speed receiver, etc. It still runs on numbers, it always will.
My understanding from a post by ian in the past regarding player weapons was that there was an "effective range" for ratings. A great example of this was the QB vison cone in prior Madden games. Once your QB went to like 75 or below awareness his cone wouldn't get any smaller. So a QB with awareness of 12 would see the same field of view as one with 74 awareness and until you go above that thresh hold you can improve. This is one reason punters can block defensive linemen in Madden, even though they are a 12, they play like a 40 or 50. I think an early blog EA/Donny More said they opened up the ratings to 40-99 or something like that. One big problem is that when it comes to a lot of the ratings [not all, but most] you can't really see a difference between a 40 or a 99 when it comes to pass blocking or block shedding or other attributes. you can stick to the default All-Pro sliders and compare the low end agaisnt the high end players and see little, if any, consistant difference in thier performance.
Use the scientific method. Create an offensive line and a defensive line. Create all the players on each side of the line as clones of each other. Same height, weight, etc. Give them all the same attributes as a "control" group. Repeat this for the defensive line. Once you have a generic [averave] offensive line make changes to core defensive attributes and make bad linemen and good linemen and tell me if you can see a difference. Then reset the ratings and repeat the process for the offensive linemen. You will begin to see, as I have tested this myself, that "ratings don't matter." At least, if they do make a difference, it is not a noticeable one that you can see and feel which would warent in franchise mode trading for, singing or drafting good players when the bad overall rated ones are cheaper. From a video game stand point, there is no reason to pay for players unless they are fast or are a good QB.
In 2k8, their ratings curve is much greater. You can see and feel the difference between Gold, Silver, Bronze and Generic players. Ian gave the impression that this was fixed, and I just don't know if that is correct/stayed fixed. I want to give Ian the benefit of the doubt, but the evidence speaks for itslef.