This is the roadmap I'm planning for lighting improvements.
Fixing crash issues
Fixing invisible/incorrect objects/lights
Adding custom improved rain/snow (I will focus on improving overcast weather)
Adding seasons without changing assets (it will be hard to do without changing assets but I will try)
Adding dynamic weather/sky instead of using settings
I will try to add night lighting (streetlights, headlights etc requires a lot of change for new lighting)
I will try to add sunlighting without making it look bad (game doesn't use PBR textures so its hard to keep details with sunlight)
I will try to change vegetation assets and road textures (this is not hard but its boring and long process)