Agree about putting crease and uncrease on the same button.
Also:
crease/uncrease should work with pre-selection, including preselection of faces and preselection of an entire object.
Selecting a subD face and clicking “crease” should crease all it’s edges. “Uncrease” should do the opposite.
There should be a toggle button for subD and Mesh vertex visibility, so we can easily check if we missed something. Occasionally I’ll be struggling with a SubD object and I’ll realize that the problem was that a face has more vertices than I thought. This isn’t always visible in faceted mode because the extra vertex can in be co-linear with two others, creating the illusion of a single edge.