I liked the flatback cars, it gave CART a distinct look from F1.
IndyCar and the FIA need to get on the same page: let F1 spec cars race in Indy. It creates a market for F1 constructors who have to R&D cars for just two racers (engines and tires too).
As much as I'd love IndyCar to be 100% independent of the FIA, it's giving us a spec series. They don't have to actually join the FIA to use F1 cars, just encourge the FIA to change rules about using F1 designs in non sanctioned F1 events. Or just have the rule declared illegal in the USA (it's my understanding the designs aren't patented/copyrighted in order to be kept secret). Teams might even give up running the USGP if they can supply 20 IndyCar races, including the 500.