If you really want to make Nationwide and Trucks popular, but keep out the Sprint Cup drivers. Do what the Trucks did on Wednesday, race at tracks like Eldora.
Eldora is probably going to be the most popular truck race of 2013, because it was a great race without too many cup drivers. (Is Newman a cup driver?). Honestly, I think that's what Nationwide and Trucks need to do. They need to race at tracks that the fans want them to race at, but NASCAR (or the track owners) don't want to put too much money into the event. Nationwide and Trucks can race at Rockingham, they can race at N. Wilksboro, etc. Use those two series to give the fans what they want and keep Cup the way it is.
I betcha that by the end of the season of them doing this, Nationwide and Trucks will be popular in their own right.