Usually, when the big heads over on the Blizzard Overwatch team decide that a change needs to be made to a map they do so for a reason. These reasons can vary, from bugs in the game, to just better aesthetics, but my favorite reason is always the subtle hints that developers try to give to us about upcoming heroes.
Source: N4G PC Route 66 Change In Overwatch Might Be Hinting at New Event/Hero