The thing with Hall is that he gets the blame for a lot of things that were Williams's fault. Even in 2011 in those Dallas games, he was put on an island with Dez and basically told to cover for 6 or 7 seconds.
Hall isn't Revis, but he's good enough to deserve a starting role. The problem isn't skill, but his contract.
While ultimately I think we could find a replacement and maybe more (either in quantity or quality) with the money we would save by cutting him, considering he's willing to restructure, we should take that course.
Cutting him creates a hole that we would have money to fill, but money =/= guarantee of adding a player. If we suddenly lose out on bidding for Lewis, Toler, and a couple others, we'd be in a heap of trouble without Hall there.
If Hall was not outright willing to restructure, and we were dealing with Hall's current contract vs. potential FA, the weight might lean towards cutting, but with Hall willing to restructure I think the weighing of options leans towards restructuring to save several million and pursuing someone with that over cutting him.