How about just making it a whole lot simpler and dispose of regional/national status, combine the series, make all the cars eligible to run the events. I don't think now a days the Majors is all that epic, people just want to race and have a lot of cars to race against.

Perhaps have an enduro/pro series as an alternate event. I think people are double dipping just to get some track time for the weekend. Since nationals are longer, this would solve the track time issue, and perhaps we would see more cars in the same number of classes, and then there would be a jump in participation.