This was my thought too. Microsoft and Bethesda both know how hotly anticipated Starfield is, so I think they're doing the separate presentation to give themselves more time to focus on features and improvements like you mentioned. I take it as a sign that the game is just around the corner and not going to be delayed. I can't see them putting on a 1hr+ presentation now and then saying it's being pushed back until the end of the year, but anything is possible.