Percy Harvin is the biggest personnel issue facing the Vikings in the 2013 offseason. Rumors, speculation, and opinions have been flying. I think the bottom line is this. Harvin is not happy with the Vikings, he is wildly passionate and emotional about winning, and he hasn't matured enough yet to channel his energies to benefit his team without creating distractions. While we fans don't know what is happening inside Winter Park, I doubt that the situation has become intolerable for the Vikings. The Vikings should hold onto Harvin. Once he gets into training camp, he will see that the Vikings offense is ready, and has potential greatness with or without him. Harvin has been a great Viking, and with an improving offensive line and an improving Ponder, Harvin will be a leading contender to take the 2014 MVP award, competing with Adrian Peterson for it. On the other hand, if Harvin does what he shouldn't and makes the issue only about himself, Harvin is not a true superstar, and trading him for a couple of draft picks would be fine. I believe Harvin will have a great year for the Vikings, and he will get a long-term deal in late November 2013.
The Vikings would do well to bring in a capable free agent or two (or three). Some names would be:
Domenik Hixon, WR, Giants
Dannell Ellerbee, LB, Ravens
Cary Williams, DB, Ravens
Ramses Barden, WR, Giants
Kevin Boothe, G, Giants
Victor Butler, LB, Cowboys
Dominque Rodgers-Cromartie, CB, Eagles
Colt Anderson, S, Eagles
Tyler Polumbus, T, Redskins
Cedric Griffin, CB, Redskins
Pat McAfee, P, Colts
Louis Vasquez, G, Chargers
Danny Amendola, WR, Rams
Louis Delmas, S, Lions
Based on the lack of free agents at defensive tackle, unless the Vikings can find a diamond-in-the-rough type in free agency, the Vikings will need to prioritize that position in the draft. That doesn't necessarily meaning drafting early. Both John Randle and Pat Williams went undrafted.
Certainly on the Vikings's list to definitely resign are Phil Loadholt and Jerome Felton. It's still a mystery why Geoff Schwartz didn't get more playing time in 2013 instead of Brandon Fusco, but in any case, the Vikings wouldn't make a bad choice by re-signing Schwartz.
I would hope that the Vikings' re-sign all their free agent defensive backs, offensive linemen, and wide receivers, except Aromashadu, who I think has not even done enough to earn another chance. Bring them into camp, at least. I think the Vikings should also re-sign Brinkley and Henderson, although one or both may end up in backup roles. In fact, I think many positions at wide receiver, DB, linebacker, DL, and OL will have open competition.
Contract restructurings to manage cap hits could include Jared Allen and Antoine Winfield. They should return to the Vikings. I hope Kevin Williams returns as well, although the Vikings probably have to ask him to take a pay cut.
If the Vikings are looking to swing a trade, Brian Robison may have more value to an AFC 3-4 team than he does to the Vikings.
EDIT: The Vikings have now Harvin is traded to Seattle for draft picks. The Vikings get their 2013 1st rounder, a 2013 7th rounder, and a 2014 mid-round pick. Obviously, this is a blow to the Vikings. Apparently things Harvin was simply unwilling to be a Viking any longer. This adds to the Vikes' need to sign a couple of free agents.
EDIT: Rick Spielman talked about the Harvin trade, calling what Seattle offered in exchange "too good to pass up."