Thurmond is a wait-and-see, in my book. However, I think the Hawks do everything they reasonably can to keep Browner. Everything that Archer said above, plus...
Browner is a key part of the Hawks run defense. There is NO corner in the league that adds what he adds in RUN SUPPORT, almost like having a LB at the CB spot. IIRC, Browner single-handedly won the game at Carolina for us last year with that unbelievable play on a Cam Newton option pitch, a play that probably only Browner makes, out of all CBs in the league. (OK, so the rest of the team helped make the W happen too) A smaller corner, Newton maybe chooses to try to run over, but Browner's mere presence screws with Newton's read, which leads to the turnover.
Plus that hit on Wes Welker in the Patriots game was teeth-rattling. Welker is one tough hombre, have to respect him, but he got absolutely LEVELED on that play, came out for a few plays, and it affected him the rest of the game. Without that hit on Welker, I think the Pats rack up a bigger lead, and I don't think the Seahawks are in position to win that game.
So we have Browner for 2 game-changing plays last year. 2 L's into W's. Not bad. I totally see us keeping him if the FO can at all find a way.