Hello,
Thank you for your compliments on the project. It's an interesting suggestion you're making, although not a very simple one. We certainly appreciate the idea and will put it on the "list" for any future edition.
Based on your suggestion we set up a sample survey to simulate the requirements you are asking for with the current Survey version. Please check the sample surveys: Resume Progress
The basic idea is not to submit the final results after answering all questions, but save the progress and share a progress code. After review and revision you can then submit the final results.
Kind regards,
Fwsmaster