I think in the traditional sense, by jamming guys and getting them off their routes, you're right Grimes can't win at the line.
But i think because of his really polished and refined technique, good awareness, etc. he does an excellent job putting himself in a position to win very early in the route. We've seen times over the past 2 years where Grimes gets beat. It happens to everyone (even Revis). But how many times have we watched a play or a replay and said Grimes got "burnt?" I'm sure there has to be a few examples, but it seems like a rare occasion. With Dunta OTOH, it's almost once a game (if not more) where there is a play where he just looks lost out there. When a corner gets burnt, when you break it down, it usually happens almost immediately off the line of scrimmage e.g. for how balanced he is with his backpedal and/or footwork. And thus when the WR goes into his break on whatever the route is that is really where separation is created and depending on that particular route, you can have a guy 5 yards away from the WR and you're in trouble.
I think if you go back and watch '09 tape of Grimes, you're going to see many more instances where he's not in position and gets burned. And it's one of the reasons why I thought Grimes was very much overrated following that season, and why I was one of the last to get on the BG Bandwagon. Now the beautiful thing about Grimes is that he improved from that year. And his improvement was drastic IMO.
And that was one of the chief reasons why I think the Falcons should have paid him this off-season. Because that sort of hard work needs to be rewarded. Mike Lombardi I think said it well and I'm paraphrasing, but you're not just paying the best players on your team, you're paying the best people on your team.
It's like being a parent or a dog owner, you don't reward/give affection to bad or unwanted behavior.
And I certainly could understand TD's skepticism (IMO skepticism is a very good trait to have as a GM) before the 2011 of giving out a contract, especially in light of the lockout. But once there was labor peace, and we saw very early in the 2011 season that there was no drop-off from Grimes, that should have been the time where a contract should have gotten done. We did this back in '08 with Jenkins and Babineaux, and I think that would have been the appropriate thing with Grimes at the time.
And now that we're a year removed from that and thus all of the subsequent events (his multiple injuries), I don't think those events really determine whether paying Grimes or not was a good/bad decision. As it's been stated in other realms, judging decision-making is less about the results and more about the process. Because the results can be skewed by random, uncontrollable events. The analogy I like to use is drunk driving.
Just because you make it home safely doesn't mean that getting by the wheel of a car tipsy is/was a good decision. There's always an inherent risk of dying/getting into an accident every time you get behind the wheel of a car, but by do so when you're intoxicated increases that risk dramatically.
In the case of Grimes, the inherent risk of injury IMO is not a significant deterrent. It would be different if he was a safety like William Moore who plays a position that has a higher inherent risk and is also a player that has a longer history of injury. Peria Jerry and John Abraham also fall into that latter category as well.
And here comes fun gus with the rebuttal in 5..4..3...