I say leave it the way it is for a few reasons.

1. You can turn up on friday if you want, you will only miss 1 round.
2. I know i dont compete at alot of events that require me to fly (because of my work) but when i do i enjoy the 4 days of racing, and if you shorten it to much it becomes to rushed and thats not enjoyable.
3. Alot of people that complain about the meets being to long are the people that lets face it probably will not turn up regardless! The haters will always find a reason not to go.

As i say just because practice starts on Thusrday does not mean you have to turn up, you could always go on Friday and save on your hotel, car hire ect ect. Then for someone like me that enjoys the xtra day i can go Thursday, BOOM we all win!