I personally think it's some kind of in joke with the design team. 1000s complained about the tiny battery icon in the first build and they end up making it smaller. It's MS' way of screwing/trolling with people.
Other possible pranks by MS:
the Windows 10 start menu (all the Windows 7 users wanted the start menu back, MS gives it back in W10 but shoves in Live Tiles as a kind of screw you to Windows 8 critics)
address bar at the top in Edge (they moved it back but look at long they had at the top)
the Edge logo (seriously)
iOS style toggle switches and circle profile pictures ("people aren't squares" lol)
hamburger menus (there was a huge outcry when this was added to the OneDrive app, now it's in W10 so much it might as well replace the logo)
Joe Belfiore's hair