Sorry, I didn't see this earlier.
Mediocre access from a secondary highway. Weak existing businesses along the commercial corridor. Strong competing shopping destinations. Wrentham and the new lifestyle mall in Sharon have better highway access and allow them to pull from a several different demographic and geographic regions. Foxboro is a destination joint, and contrary to the suggestion earlier in the thread, can't survive on football fans alone. Hell, don't take MY word for it. The Kraft family used some of the same descriptions when they were looking to put a stadium on the South Boston waterfront.
Having said that, if their anchor tenant is any indication, I think it will do fine. And Patriots fans should rejoice because the Kraft family has provided a perpetual incentive to winning football. Nobody goes two miles off the highway to shop at Detroit Lions Mall.