There need to be a few changes. Here are my suggestions
Head coach Brad Childress - Consider relieving him of his post. For all the good he has done, it hasn't been enough yet. Major changes need to be made. Can Childress make the changes necessary to take his team to the next level?
Defensive coordinator/assistant head coach Leslie Frazier - fire. He's bad.
Running backs coach/assistant head coach Eric Bienemy - fire. He's terrible. AD has not improved one bit since he became a Viking.
Offensive line coach Pat Morris - fire. Try to hire Mike Tice.
Defensive backs coach Joe Woods - fire
Keep the West Coast Offense. Change the blocking scheme. Our large offensive linemen are better suited to man blocking. No longer use a fullback on running plays, as it doesn't suit Peterson's style. That allows for an extra tight end or wide receiver. It makes more sense to have Percy Harvin on the field than a Tahi or other fullback.
On defense, keep the 4-3 scheme. Change to man coverage.
Quarterback - When we look back on Vikings history, we can see that a key problem has been not drafting quarterbacks high often enough, and getting rid of rising young quarterbacks. After Tarkenton, the Vikings got lucky in getting Joe Kapp. Then he left. When Tarkenton returned, the Vikings went to three more Super Bowls. Kramer was talented, but had off-field problems and injuries. Wade Wilson did well at times, like in the '87 playoffs. Rich Gannon was released too early. Daunte Culpepper was a good draft pick, but the Vikings failed to draft his successor early enough.
Wish Favre the best for his retirement. It has been an honor having him play for the Vikings. It's too bad it hasn't worked out better. Re-sign Tarvaris Jackson as he is probably going to be a career backup quarterback, and he already knows our system. He is a Viking, and we must stand by him. Draft Greg McElroy or Andrew Luck. Hold an open competition between Jackson, Webb, and the newly drafted quarterback to determine who will start next year.
Running back - Re-sign Adrian Peterson. With a new running back coach he can finally improve as a running back in the NFL. Without that new coach, and the result of him playing better, he wouldn't be worth re-signing. Currently he is only a one-third running back. All he can do is run. He can't block or reliably catch the ball. To credit Peterson, he is capable of learning new things, as long as Bienemy has nothing to do with it. Under Bienemy's direction, Peterson became a fumbling machine in 2009. Then Peterson stayed away from Bieniemy for the off-season and learned how to keep the ball on his own. Fire Bienemy, who probably hurts the Vikings more than he helps. Furthermore, Gerhart has done very little under Bienemy.
Wide receiver - Cut or trade Berrian. Do not re-sign Sidney Rice. While I love almost everything about Sidney Rice as a football player, he is injury-prone. His one healthy season was 2009. He can't help the team from the sideline.
Trade for Larry Fitzgerald. He will be our possession/threat receiver. Harvin is the threat/slot receiver. Look for a deep-threat receiver who can learn route-running to be our #2 wide receiver.
Offensive line - Trade Bryant McKinnie. Sorry, but it's time for a change at left tackle. Draft his replacement.
Tight ends - Probably just keep them.
Linebacker - Release or trade EJ Henderson and Ben Leber. Re-sign Greenway.
Secondary - As we look back in Vikings history, a lack of continuity in the secondary has hurt the Vikings. We need to keep our good players and our young players with potential.
Special teams - Longwell's kickoffs are terrible. Get a kickoff specialist. If Longwell does not support the move 100%, trade him or cut him. Get a new kicker.