Many aesthetic enhancements See pictures
Auto-closing hangar doors, and airlocks between bays.
Decorative ventilation system
More aesthetic tweaks coming...
Plex-lifts are now enabled with logic to provide a smooth and intuitive floor-changing experience. (http://gaeasson-shipwright.blogspot.com/2014/07/logical-lifts.html)
Many other refinements:
All systems are now astronaut-accessible
Semi-decorative section reactors.
Simple industrial stations on the factory decks.
Minor decorative and aesthetic tweaks.
Improved Signage
Many added details
improved hangar deck.
Back alleys and service ways.
Color coded station quadrants so you don't get lost.
Hotel rooms
Cafeterias
Better supplied medical facilities
Warning blocks near hazardous areas
Better lighting on the hospitality decks.
Signs
More logic