It looks like there have been some major changes in the route. There may be a few reasons for the routing choices, including small towns off of the main roads not wanting to be inundated by 8000 cyclists, and being inundated twice can wear on the nerves. It may also be to remove shortcuts, the bigger roads tend to be more direct. I wasn't particularly happy about the routing last time. I recall in 2011 the roads used were quieter. I thought maybe some of it was just population growth and more car usage.
At least bike lights have gotten better than in 2011. There were lots of people using bright lights that would light up the sky, and more importantly, the top floors of people's houses. Now, most people are using lights with a cutoff so they mostly light the road.