The decision to pass on Oher in the first round is telling. By giving up an exceptional OT in favor of a flashy new weapon, the Vikings are favoring Tarvaris Jackson. Here's how.
Harvin is a dynamic player who can, if used properly, get the ball on any spot of the field and be used to misdirect opposing defenses. He can also be used as a release valve for a quarter back under pressure who needs to get rid of the ball.
These things help a quarterback who A) doesn't have stellar pass protection, and B) often makes poor decisions trying to force something deep. The latter sounds like Tarvaris Jackson, and the former sounds like an Oher-less Minnesota offensive line.
Oher is a great player who excels at all aspects of an OT's game. Phil Loadholt is an enormous player who run blocks very well but struggles against speed rushers. Good runblocking favors a run-heavy team (like the Jackson-lead Vikings) and poor pass protection matters less when the quarterback is as mobile as Jackson is.
Sage Rosenfels is more of a defense reading, pocket passing quarterback who would do almost as well with one less weapon (Berrian/Wade/Shiancoe/Taylor and the occasional play to Rice, along with AP at RB, should be plenty) but who would perform much better if given a solid 3-5 seconds to get rid of the ball on most passing plays. Oher would've given Minnesota the chance to do this, Loadholt's more of a longshot.
To me, it seems obvious that the Vikings aren't interested in an open QB competition this year as they are at having someone better than Gus Frerotte behind Jackson. I was optimistic about Rosenfels, but these developments will hurt his ability to help the Vikings win. Minnesota's best hope now lies with a consistently healthy and hopefully improved Tarvaris Jackson this year.
I'm OK with 10-6 as long as Minnesota puts on a better show in the postseason this year.