I believe one day we will be able to do that in NL (maybe NL 2) but not only do I want the sun to move, I want to be able to create animated scene objects by using some sort of moving texture or something. Also to make the environment look better rides and scene objects should cast shadows on custom terrain and on themselves.
I dont really think that is such a realistic idea. The big difference is that you can spend numerous hours straight playing RCT for that time lapse, but in No Limits I dont really thing anyone spend that much time riding the same ride. You also already have alot of options for environments if you want to see a ride in a different light. I just dont really thing anyone spends that amount of time on one ride to really make use of that feature.
Also with the lagging framerates on a lot of peoples computers, im guessing that would just worsen the situation.
IMO, the only things that NL really needs are the dive machine, the fourth dimension coasters, the rocket and Intamin looper trains and the B&M Flying Coaster. I guess it would be awesome to have the ability to make animated 3DS objects though.