It will be more efficient if the custom printout or design form layout is shown even if the workflow is closed. This prevents the people from downloading/exporting the form just to see the information inside.
Thank you for submitting your idea. We understand the desire for it and will consider it for a future release. We are always looking to improve the forms experience and by adding a print preview instead of requiring a download could help users work more easily with their data. We will update this idea of we make progress on this work.
This would certainly be helpful if the preview view when a form is closed is the print view. The current closed preview view completely changes the form formatting