I feel the Seahawks comments are missing something important here. Athletes want to be coached. The expression, give an inch, take a mile comes to mind here. The Packers run a tight ship and that will bode well for someone like Percy Harvin. You keep him on a short leash (for lack of better words) and he won't be able to bite as many people. If he pushes the cusp, you cut the cord.
The Packers are operated much more like the Patriots than the Seahawks. The Seahawks most likely gave Harvin a lot of rope to hang himself and he did just that. So, give the guy less rope.
I would jump at a one year incentive based contract with a per game bonus to which the Packers can cut the cord at any time with little to no financial consequences.
Look what the Vikings and Seahawks were able to do with Harvin (when available). Imagine what Mike McCarthy with AARON RODGERS could do!
The only problem here is I think McCarthy gets too cute at times and having a toy like Harvin might make him borderline absurd on the cutsie stuff.