To change from auto-save to showing the Save As dialog: click the Options (gear) button, and under "Show Save As dialog each time" click the Yes bubble.

Could you let me know the site where you don't get a useful file name? I'm not sure the add-on can detect the intended name, but I can take a look. (You can contact me at jscher2000@outlook.com or using the Support link on the main page.) You also could try using the IE11 button in those cases -- it doesn't change the format, but modifies the request to the server to try to get whatever format they offer to older browsers.