We're all clearly working off of incomplete information but I have to disagree with most of the theories about anyone doing anything 'wrong' on this play. I believe the play is run exactly as planned and the Vikes just had the perfect defense (and disguise) for this and played it perfectly. With that preamble out of the way, here's my take after going back and watching the whole play again, especially the pre-snap:
As others have mentioned, RW clearly has Willson as his first read. He's running the slant which first requires moving the middle linebacker-and this Jackson's job(sort of, complicated by my 2nd paragraph). His action has to immediately threaten the flat and force the MLB to come with him. The corner does a great job of getting in front of Willson, much like a very painful play that most of us have nightmares about, and RW holds the ball rather than try to force it in.
As I mentioned earlier, I think the Vikes did a great job of disguising this pre-snap. Others above have said that RW should do a better job of getting the defense to show their hand and see this blitz coming. On the first dummy count, the MLB shows that he's coming, or at least gets Russel to believe that he is. If that actually were to happen, that would mean either both LB's come from this side (unlikely and an easy TD for Jackson) or the OLB has coverage on Jackson. This leaves the middle more open for the throw to Willson and Jackson's route still has the same primary function: keep the LB out of the way for the slant. RW would go to Jackson for his second read, and with the MLB coming from Depth, he'd have a little more time to make the throw than he had in the actual play. This probably would have been enough to hit Jackson across the middle, or possibly, still go to Willson as he starts to cut back outside after the CB commits heavily to the slant. The main thing I look at is the Vikes show a blitz the likely will send more defenders than can be blocked.
Lastly, with the benefit of knowing what the defense is going to do, it's easy to say RW should have changed his read to the three receiver side and DB would have had TD numero 4. But what's to stop the Vikes from dropping the LB from that side into coverage in an alternate universe? Just cause that's how it played out this time, doesn't mean it was the only option.
So that's what I see, but dissenting opinions are welcome.