It's best to avoid the early days of outside free agency. Non-elite players, at non-premium positions (interior oline, off ball linebacker) are going for bigtime money that they'll likely be unable to play up to.
The Hawks are in a good spot where they have two starting OTs; 3 quality WRs; two RBs; 2 starter quality edges; and are fairly deep and young at CB.
OT,WR, Edge, and CB are "big money" positions that they are fortunate to not have a desperate need for. Their needs are at non-premium spots - Interior oline, off ball linebacker, safety, and TE depth (they're smart not to be paying top of market at those spots).
The guys they've let walk are largely replacement level (aside from Brooks, who I think is a quality player with some Pro Bowls in his future). And their big keeps - Williams and Fant are the biggest pure talents of all their UFAs. I like that MM and Grubb got into the film/evaluations and came to that determination with Williams and Fant (that's a good sign, as they came in and looked at both without any prior biases).