As I write this, the Vikings most important coaching need has not been addressed yet - Offensive Line Coach.
Currently, the Vikings have co-offensive line coaches Andrew Janocko and Clancy Barone, who were given these positions after the death of Tony Sparano, who had been offensive line coach for a couple years.
Janocko had limited experience as an offensive line assistant before being elevated to co-offensive line coach (more or less by default, given the timing of Sparano’s death) while Clancy Barone was moved from TE coach. Barone has coached offensive line - including under Gary Kubiak - but without much success.