Its going to take time to finish all the changes for new PBR lighting system. I see a lot of people want sunlight/nights/dynamic weather/day cycle etc soon as possible. If you want I can spend like 1-2 weeks to improve default lighting system so you can play with it until I finish new lighting improvements.
What I'm going to change for default lighting system :
Improve foliage rendering like I did in lighting improvements
New tonemap, HDR -> LDR for better colors
New reflection system (Screen Space Reflections) together with default reflections
SSAO improvements
Maybe some fog changes