I looked into this and it turned out to be easy since we already had an approval button. I added a config setting to also show it for editors when a draft has not been submitted but it is false by default so you'll need to add this in user.config:
<add key="WorkflowShowPublishForUnSubmittedDraft" value="true"/>
then it will work after the next release or if you deploy a build of the latest source code.
Best,
Joe