It did change though. I have not time to make comparison shots in Duscae and Platinum Demo at different times of day but yeah, it did change. It's not fully gobal illuminated anymore and they scrapped a few other lighting effects.
Here's great footage of the lighting in different times of day including weather change. It is pretty recent too:
https://www.youtube.com/watch?v=kYryrG6_ugU
Lighting is different from Duscae...but it still looks good and certainly not worse than in other open-world games.
Episode Duscae just had different weather and atmospheric effects that was locked to those settings at the time. You can still get the same atmosphere and bloomy look to the sky lighting as well as what we're seeing more recently going by their siggraph media.
Duscae's lighting could look pretty flat too around mid day. Their more recent screenshot of Duscae looks better imo.
ED
Recent screen