I think those are are legitimate points about Cook. I don't agree with all of them, and agree with Brock that I liked Cook better coming out. I see some red flags with Barkley. I don't think it's as black & white on either side as both of you are saying.
For arguments sake - the "best RB since Adrian Peterson" was also used for Trent Richardson -
http://www.nfl.com/combine/profiles/trent-richardson?id=2533032
"STRENGTHS Richardson is as compact and coiled an athlete that the running back position has seen since Adrian Peterson"
DMoney nailed it that he was overrated, and he took a lot of shots for saying it at the time
Using ESPN, here's the top rated RB's since Peterson:
07 - Peterson (98)
08 - McFadden (98)
09 - Moreno (94)
10 - Spiller (95)
11 - Ingram (92)
12 - Richardson (97)
13 - Lacy (88)
14 - Hyde (88)
15 - Gurley (92)
16 - Elliot (93)
17 - Fournette (93), Cook (90)
18 - Barkley (95)
As Brock said, Barkley has had some bad games Barkley averaged under 3.0 ypc 5 times in his last 18 games - against Ohio State, Mich St., Rutgers & Indiana (twice). That only happened to Cook 2 times in 38 games.
I've got no problem if you think Barkley is better than Gurley/Fournette/Zeke/Cook - but also think it's legitimate if you don't.