I don't think it has anything to do with it being PG vs Attitude. When there is a decent story line, people still get interested.
I think one thing that would help is having less titles. It would be more interesting to have say Orton, Shameus, Big Show, Cena, CM Punk, Ziggler, and any other main eventer that I have missed all gunning for one belt (while having their independent story lines). This way, we wouldn't have to watch the same two or three people always main eventing PPVs back together.
Same thing would apply for the other titles. More competition for the titles, less belts, everyone wins.