The Vikings have the potential to be good in a few years. I feel pretty comfortable making such a statement; and I do not think it is too controversial to make. A lot of the pieces are in place for a successful rebuilding process.
The major caveat to such a statement is that even if the Vikings do rebuild successfully, they still have to play in a very competitive NFC North. It's not like they are chasing one team. Nay, they have to catch up to three (I think) playoff caliber teams. That is tough in this league - but crazier stuff has happened, I suppose.
That said, the Vikings did have a lot of areas of concern this offseason, and the relative success of their Free Agency was never going to fix everything. The plethora of drafts picks this year, however, should go a long way to solving these problems. I particularly like how aggressive the Vikings were in the first round, making some smart moves and still getting excellent players that also fill needs in OT Matt Kalil from USC and S Harrison Smith from Natre Dame.
Jump to the third round for another addition to the secondary with CB Josh Robinson from UCF. It's the fourth round, however, that may be the best round for the Vikings (with obvious exceptions for the first). Adding three players, the Vikings went a long way to potential upgrade their passing attack, which was a big area of need, with WR Jarius Wright from Arkansas, TE Rhett Ellison from USC, and WR Greg Childs from Arkansas. From what I have read, though, Ellison will not be much more than a special team type of guy who can potentially play fullback and TE when necessary. Also, when in doubt, collect all the Arkansas receivers!
The only other multi-pick round the Vikings had was the seventh, in which they chose LB Audie Cole from North Carolina State and DE Trevor Guyton from California. They join sixth round choice K Blair Walsh from Georgia and fifth rounder CB Robert Blanton from Notre Dame.