I'm not convinced that letting Arch walk will be the best move. The guy was a playmaker until...Larry Marmie arrived. Even then he managed to make some amazing plays (forced fumble and TD against the Bucs in 04'). The guy has a nose for the football and is always one of the leaders in tackles. A lot of people didnt like his tackling. Dont forget, it's really hard to make a play when you are put out of position from the start (Larry Marmie) The entire defense stunk last season and Arch was one of the guys who kept it from being worse.
Tell me, what changed from 03'-05'? Arch was a playmaker in 03' on an opportunistic defense. He played closed to the line and terrorized QBs and RBs. In 04'-05' he played in coverage for most of the game and rarely saw the line of scrimmage. Ok, so he went from being used as a blitzing safety (his strongpoint) to being used mainly in coverage (his weakpoints) The change was Marmie.
I would do anything possible to bring back Arch. It's hard to find Strong Safeties that can be used like he can be. He's great when used near the line and is average when used mainly in coverage. I want him back. I expect him to return to his 03' form back in a scheme that doesnt have him playing FS from the SS position. I'd love to see him back in Blue and Gold.