Export diagrams menu
I think there is no reason for the Export Diagram option to be on the Diagram menu. First place I went to when I wanted to export was File (there actually has an Export option there). I think only one option at this submenu would suffice (something like File > Export > Current diagram) and having the desired format selected on the save dialog. On the current menu options I'm punished for wanting to changing my mind and I even have to type the expected extension for the file or it's created without one.
I'd go as far as to say the entire Diagrams menu is unnecessary but that is another suggestion. Let's focus on exporting here.
Available at 2.0.0-beta5