Scenario A: Paps has a terrific year, Sox throw money at him because they don't have other needs, everyone's happy
Scenario B: Paps has a mediocre year, Sox throw slightly less money at him because that's still pretty good (and decently cheap), most people are happy
Scenario C: Paps collides with Adrian Beltre trying to cover 1st base, misses season with rib fractures, toughness questioned. Brought back on relatively cheap contract, some people are happy.
Think it's more likely that Papelbon is brought back in each of the above cases. Although, I think that if Papelbon has a good year (i.e. significantly better than last year), that's the least likely scenario for him to return.
I don't think that he's lost anything from a stuff perspective, I think that it's more of an issue of approach and that is fixable.