i do thing a little different when it comes to a 3-4 beacuse of the endless matchup nightmares. as the cowboys i had d-ware as both a RE and a OLB i had spencer do the same with ratliff playing le, nt, and re.
take ray edwards and move him to outside linebacker. keep kevin williams but put him at the le, jared allen as a RE on runs and flex him out at olb on some pass plays. do your best to aquire jay ratliff (a monster on madden 11) put him as the NT which is instant pressure.
with the vikings, i would also consider a complete secondary overhaul. i just don't like their secondary.
if your planning to use joe webb as your starter pound the ball atleast 35 times a game, with his low ratings having him sling it more than 15 times is not going to work well. use a 3 headed attack. use peterson, gerhart, and go for tasard choice for draw plays.
your draft picks should be focused entirely on your secondary, go for the best corner available