Warning before closing
With autosaving documents in cloud, when I accidentally hit Cmd+Q it closes instantly the XD app and all opened documents without any warning. It is annoying because I have to reopen all previously opened documents.
Google Chrome has this option that warns you to press Cmd+Q twice to close the Chrome (in case you hit it accidentally, which is not that difficult having W, that closes single document, sitting right next to Q). It also gives you the possibility to reopen all previously opened tabs, this might be useful too.