It seems for The Royal that they added more teambuilding events , which were really lacking in the base game. Good thing, the team might look more like one and it should be easier to like the characters. They maybe also modified some dungeons with other passages, maybe they made them shorter (other flaw of the base game). Kichijoji is a nice place to add too, I had some dates and work shifts there, should be fun to go visit in game.
Will wait for more information, but I'm interested. Not sure yet about full price though.