In Revit, the "Open" command has a default option ("All supported file types"), or you can click on the arrow to get more options.
Why can't "Save As" do the same thing? The non-applicable options are already grayed out, and I personally have never used the Library option.
I know it's just one extra click, but it's a pointless (and frequent) one.
Can't find what you're looking for? Ask the community or share your knowledge.