Jake,
I'll give you some of my personal experiances on going from Regional to National racing and why I say those that focus on National Racing will more than likely run less events than they did racing Regionals.

In 2007 I raced in NEDiv in GTL, 6 National races over 5 weekends plus the Runoffs. It took 15 vacation days to cover the Friday race days (LRP & Pocono double), the Runoffs and travel time. If I stayed within a 4 hour drive of my home I could have raced 8 weekends at Regionals and used only 4 vacation days to do it. And let’s not forget the fuel costs for towing. ($1200+ in fuel costs to go to the Runoffs at $3.25/gallon, make that $1600 for 2008)

By focusing on National racing the idea of damaging your car at a non-point Regional becomes a huge concern when there is only like 8-9 events in your Division you can earn points at for a Runoffs invitation. This is a huge detraction from entering Regionals for these drivers.

This is why I say the total event entries (Regional & National) will drop for any particular Region rather than stay even. I suppose everyone will have a differing opinion on what could happen and until IT becomes a National class no one can say with any certainty what the results will be. I don’t have the numbers but the SM statistics might show some trends of giving a Regional class, National status regarding total annual entries.