Cousins should give us high level and consistent play from the most important position in the game. But it comes at a high cost - at least high for now. His contract may look more reasonable in a couple of years, but by then he will be in line for a new (bigger?) deal. Two of the other better teams in the NFC (Philly and L.A.) have low cost QBs and are exploiting the advantages that brings.
Atlanta and Carolina, two more good NFC teams, are more like our situation. Brees is giving N.O. a break on his salary, like Brady has done with N.E., in order to let his team compete. Finally, GB will soon, hopefully, have the most expensive QB in the NFL. Unfortunately, he is also so good he does not need very skilled players to be very productive. (Where would you rank Cousins in comparison to Rodgers, Brady, Brees, Wentz, Ryan, Newton, Goff - I only included 1 AFC QB?)
The other key area where the Vikings have, and can maintain, high level performance and stability is in Zimmer and his coaching staff. I know we will lose coordinators regularly if we are successful, but that comes with being successful. If you want to include Spielman and his group with Zimmer and the coaching staff, I would not argue with that. But Zimmer has been key in turning this franchise around. He should have the kind of job security that the very top coaches enjoy, even if he may not really be in their ranks (yet).