I'd like to see the ability to close the active tab / code document with CTRL+W and CTRL+F4. These shortcut keys are widely adapted and I'm a extremely frequent user of them.
Actually I wouldn't mind seeing them being firstly picked up by the topmost/active dialog before it is used for the tabs, as I feel more reluctant to use/try ALT+F4 to close dialogs as this in many applications closes the main window and could potentially create more fuzz to reopen the application and open document(s).
Sounds good to me.