Well, as you said, it can be helpfulp in eliminating the extremes and that's exactly what was posted in the OP. If you simply eliminate the bottom 2 groups, you get rid of 40% of the RB's and have almost no chance of missing a top prospect. When you're looking at 1a vs. 4a, you're splitting hairs to be honest. But, there is something to be said about the group listed in 1a. They truly are the cream of the crop. It's not to say that a guy in 4a can't be a stud, but the top studs seem to fall in 1a more than 4a. It's a guideline, though, not an absolute. It should be reassuring if someone you have ranked high falls in those top 2 groups and a red flag if they don't.
Yeah - that's the way to think about it Gian - all you're doing is improving your odds. I hate that those categories won't die now though!Anyhow, there are a ton of weird backs in this draft. Almost more than the last ten years combined:
McFadden - ridiculously low BMI (best guess, full on bust because he'll be used as a bellcow and that's not his NFL niche)
Chris Johnson - sub-200 pound RB with ridiculously low BMI yet still drafted in the 1st round (best guess, returner/gimmick back - not FF starter)
Forte - low BMI, non-major conference (best guess, he's good but Chicago may screw him up)
Smith - low BMI, non-major conference (best guess, he's good but Detroit will screw him up)
I'm honestly not sure what to do with those guys, so my best guesses are still pretty subjective. Otherwise:
Mendenhall, Stewart (safe as it gets - Steven Jackson, Willis McGahee)
Felix (safe bet to have a few good years - could be the best back in this draft, compares to Clinton Portis before he beefed up)
Rice (very borderline - probably career 3rd down back/backup along the lines of Maurice Morris)
Slaton, Charles, Choice (undraftable - stay far away)
Torain and Thomas Brown are both worth watching VERY closely - there are legit reasons other than talent they might have been drafted late.