Actually, you could do this. It would be an (ahem!) "difference of differences" design. What you would be testing is whether a change in offensive system led to better recruiting, controlling the relationship for "staff energy" and increases in resources. I say controlling here because a) we were planning an increase in resources anyway and b) staff energy would be a doubtful factor since I'm pretty sure Paul's staff gave their all in recruiting. Staff energy would be hard to measure, except, perhaps, by mentions in the press or something like that. Controlling for resources would be much easier.
You would have to wait a year or two to get trends; you could do it after next year, but trends are more reliable. Then you pick a couple of dependent variables (average stars and recruiting rankings would do it) and look to see if the change in offensive systems led to a significant change in the coefficients for years before and after the new system was adopted. You'd be controlling for resource changes and perceived "staff energy". That would give you a clear shot at seeing whether changing from the TO to a shotgun spread made any difference in recruiting.
As was pointed out above, chances are all this work - and don't look at me to do it - wouldn't change people's opinions, especially since the change we can expect will, imho, be too small to register as significant, given the small size of the datasets involved and the likely small shifts in average stars and rankings. (I think Coach will be able to get us on a par with VT in recruiting short term, but we'll see.) But it could be done.