You definitely have to execute the play correctly to take advantage of mismatches. As of now, under Philben, I'm just happy to see that they are putting players in areas where they can create mismatches and giving them more of a chance to succeed. The offense dictating to what the defense has to do is something we haven't seen for quite awhile with this team. It gives you reason for hope, which is the exact opposite of seeing the Wildcat being run on 3rd and 8 from our opponents 25 yard line or play action pass on 3rd and 10+.
Back to the issue of Vontae, I just wanted to make sure I remembered this right because it would be a disservice to disagree with you without being sure. I did not recall Vontae being used in the way that you describe. He was strictly right perimeter the entire half. He had right field and Smith had left field.
The "shutting down" of Wes Welker in the first half is a bit of a misrepresentation. He was targeted seven times so trust me when I say he was getting some opportunities against our defensive game plan. He has two catches for 20 yards which is bad for him. But if you look at it, three of the incompletions in that first half were just all Tom Brady's fault as he had what was really a terrible half for him. He was off all over the place. I remember that, it was very strange seeing him play so poorly. There were definitely three catches in there that could have been had for medium yardage, maybe more.
One attempt in Welker's direction was broken up by Vontae. This was not any special game planning or moving around of Davis though. Welker was lined up as the perimeter receiver to Vontae's side. He was a little tighter to the formation, but either way in the Dolphins' zone scheme that put Vontae on him. The formationing led to a secondary audible where Vontae played off, Tom Brady threw the ball a touch late on a curl pattern and Vontae closed on it, broke it up. Another play Sean Smith broke up with excellent coverage. Again, Welker lines up as the outermost receiver to Smith's side, he draws the coverage. What Smith did was just jam the ever loving **** out of Welker then used his long arms to go through him and break up the ball.
Other plays, Welker was covered pretty well by combinations of Will Allen (who was our slot corner) and Kevin Burnett. When Yeremiah Bell had to cover him, he really did a poor job, and those were some of the plays where you saw Welker either caught the ball or was open and Brady threw off target.
As for why sub out Vontae Davis for Richard Marshall, I think you've got to take this one at face value. Either Vontae Davis is a little nicked up and they have to regulate his reps, or they're a little unhappy with him and they want to see how Richard Marshall looks on the perimeter. Sean Smith has been a top performer during the OTAs and Mini Camp along with Training Camp thus far, and he supposedly did a really good job with the off season weight and conditioning program, so that could be why you don't necessarily see him subbed out for Marshall.