If I were GM, here is what I would do to make the Packers contenders. I would use all tools in the box including trades and free agency.
1- I would call John Schneider in Seattle and swing a deal for Richard Sherman giving up Lindsey and Cobb. Seattle is desperate for o line help and this draft is not deep in o linemen. Salary numbers are similar so you don't break the bank.
2- I go into free agency and get the best available cb like Trumane Johnson and sign a veteran pass rusher for depth like Demarcus Ware If you added Johnson and Sherman to Hhcd and Burnett you would go from the worst secondary to potentially the best.
3- In the draft I go with McCaffery in the first and package my second, fourth and second fifth pick to move up into the top half of the second round to pick the best available pass rusher, hopefully TJ Watt. McCaffery and Ty would be a two headed rb monster and make up the lost production from the slot where Cobb worked. McCaffery would instantly upgrade special teams to a dangerous level.
4-You move CM3 back to the middle and resign Tretter to be center, Cook to be TE, Lang at guard and Perry to be OLB. All the other free agents can go.
5- in the third and fifth rounds I pick a guard and d lineman. In the 6th and 7th rounds I go with WRERS hoping I hit a diamond in the rough.
Under that scenario, defense and special teams go way up in quality perhaps to top 10 or better. Offense would be ok and potentially dynamic with the addition of McCaffery. I don't see this scenario as too impossible to pull off. If it happened, Packets would go from a perennial 10-6 pretender to a legit if not leading SB contender.