There's two things I like about Welker that make me think of Dwight. One, he's elusive and tough. Two, he's not a high-value #1 starter that you'd be afraid to risk in the return game.
Hobbs is every bit the returner that Welker is, but I don't want to see him out there. It's nice to have a guy like Welker returning punts, so if he's out for a game, your secondary (or receiver corps) doesn't collapse from the loss. Dwight provided terrific depth and in the end, giving him up has a quiet impact.
It wasn't a mistake losing Givens for the many millions, but I forget how much it would have cost to have kept Dwight and perhaps that was a mistake BB shouldn't have made.