Nothing saddens an oval racing fan more than a wet track. I don't think there is a single circuit racing series which races oval-type courses in the rain. Ovals are dangerous to race when there's a lot of water on the race track because you need the best slick or soft tires to grip the race track as best as possible. If NASCAR (or any series for that matter) came off with rain tires for an oval course, then it not be a good fit since you need as much traction as you can get, even on slick surfaces. Then too, NASCAR "stock" cars aren't designed very well for wet oval courses.
Your question has GREAT relevance in NASCAR road racing, however. I can remember years ago in a CASCAR race that it rained at Mosport, and the cars used rain tires and had a brake light on the rear windshield. The cars would have to be better able to race on a wet road race course. Can you imagine a road race where it's wet all day and 43 drivers are all jockeying for position? It would also boost driver talent if there was such racing. The big reason is because a bonehead move (for example, ramming a guy off the track like T. Stewart did to M. Kenseth) carries potentially bigger risk. This is why I enjoy road racing more than ovals, because it brings out the best in racers accustomed to ovals all the time.
I hope that solves something...