A lot of the incoming changes were prompted by the upcoming inclusion of the Romulan faction. Using the present tradition of coloring everything on the UI to represent a given faction (in this case, that would mean a crazy green glow) didn't seem the way to go. Instead, a complete revamp was begun. The revamp includes interchangeable color schemes, oodles of customization options, and more immersive elements.
Be sure to check out the most recent Captain's Log to get Teri's take on the UI changes and other tasty morsels on the Tribble test server.