That would mess people up. Most people like to sleep when its dark.
we like it, but a lot people already work at night so it is not impossible. and if you don't like the dark your hours would just change see previous post.
Now one of the pros to this situation is for your global companies. It is easier to schedule meetings, and work together.
Especially as we move more to the internet where it doesn't matter if the sun is up or not. if you say lets have a chat session at 2100 everyone knows what time you are meeting.
If you run a business and you say your hours for your business are 2:00 - 10:00. Everyone around the world knows when 2 - 10 occurs. So when someone from singapore calls there is no calculating to do.
Ideally it would be best if all business world wide simply worked 9-5. Or at least during those times. Some people would see the sun rise, others would see it set, but we all would have the same time.