I'm sure if you're expecting Wilson to be the deep safety against someone like Mike Wallace, then he's going to disappoint you with his coverage abilities. But I doubt that's the kind of coverage he was brought in to provide.
In recent years, the Patriots have been burned for a lot of deep plays statistically, but those are typically measured as 20+ yard completions. Where I've seen the most of these plays given up were not over the top, but were on the sidelines in 1 on 1 coverage against a corner (which we're hoping Talib and Dennard can stabilize), and in the 10-15 yard gap in the middle of the field that seems to exist between our linebackers and our safeties.
Wilson's value will be in making that zone a more punishing place to do business. I don't expect him to shut down a lot of passing attacks, but if he can make a few receivers a little more timid, we may see more alligator arms on crucial third downs. That, and he should provide some much needed leadership and coordination for a young secondary.