Interesting stuff ... so far, Tim Howard has only allowed 7 goals on 53 shots on goal (13.2%). That may suggest that defense plays a substantial role in determining a keeper's save percentage. In MLS, Howard let in 18.75% of the shots on goal he faced (18 of 96), and presumably MLS shooters aren't as good.
While I'm on a Howard tangent, I think it's really interesting that Johnny Walker has allowed far fewer goals per game than Howard (1.02 vs 1.33), yet Howard's record was 6W-4D-3L and Walker's is 4W-5D-6L.
The thing that's changed is that the Metros used to be an open, attacking team that allowed 7.1 shots on goal per game. With Walker, they feel the need to protect the goal more, and they only allow 4.7 shots on goal per game. Much has been made of Clint Mathis's slump, but IMO, it's more a matter of playing style.
A couple bits of site feedback:
1. Typo of "Strengths"

2. It might be nice to include team totals as well as game-by-game shooting stats