Its simple really; Bush makes a better backup at Woodson's position (Nickle corner, Physical blitzing almost safety/lb type role, covering TE's) than he does at William's position (Cover corner). Woodson is clearly a better cover corner than Bush is, while Bush play's Woodson's position better than any other on the field.
But I too would have liked to see Shields, with some safety help, on smith.
Edit: I think I misread your post, I think we're agreeing here but I've written my post as if it was contrary to your opinion.
Originally Posted by: earthquake