Notice the nice ascending order? Floor, then ceiling and at the top Roof. It's even logical, or at least to me it is. Next is the Revit MEP Architect Ribbon and the Build panel.
This time around they are jumbled a bit and not in ascending order. They could be but they aren't. Roof is also off to the side at the bottom and Column is where Roof ought to be (could be).
Last is the Revit Structure Architect and Site ribbon tab and the Architect panel. In this case we just have Roof because Floor is elsewhere, part of the structural set of features and ceiling is deemed unnecessary. I suppose this sort of inconsistency doesn't really affect many users but they could be more consistent?