Strange - I also watched every play. I was fairly impressed.
He looks like a fluid receiver and Bradford clearly likes him as a dump-off option. 
He also has shiftiness and good vision hitting the hole. Runs with power. 
http://m.vikings.com/media-vault/videos/Dalvin-Cooks-Top-5-Preseason-Plays/a81b9dd6-95d7-4ce5-a500-f7062a58e7ff
don't know how anyone claiming to have watched him could be anything but impressed with the kid. 
Vikes say he's a hard worker, handles every situation, lines up shotgun, I formation, split out. Hard not to be a little excited when you hear an NFL coach gushing about a rookie RB. 
http://floridastate.247sports.com/Bolt/Dalvin-Cook-draws-rave-reviews-from-Vikings-RBs-coach-106749069
And hard not to get excited when you see a rookie RB straight up win the starting job in training camp. 
And here's an NFL writer who loves what he sees from Cook. 
http://bleacherreport.com/articles/2726300-dalvin-cook-could-be-the-breakout-rookie-nobody-is-talking-about
its just weird that so many people who write about or coach the NFL are watching this kid and loving what they see, while you remain...unimpressed. 
Also weird,  I just spent 5 mins googling and couldn't find a single word indicating there would be a timeshare-share. Maybe you can post your link that substantiates your statement about RBs splitting carries in MIN? 
Thanks in advance.