Personally, any Rebellion sequel will need to overhaul the outdated UI. It is a big issue to me, bring it into the modern era. I really like Sins of a Solar Empire's UI. It is very clean, strategic zoom in and out of the entire map, drag-and-drop commands, easy Empire tree. Messages don't hog the screen. For those information that absolutely requires a new window (research trees, etc), it lays over and does not stop the view of messages, resources, etc. Sins sets the standard for an intuitive, easy interface. Window-clicking and dialog boxes need to go.