Ideally, submitting the flight plan directly from VFRNAV would be best, of course, but that would be a very extensive change.
What would already greatly simplify filing the flight plan, though, would be an “Export” of the flight-planning waypoints to the clipboard in the format expected by the flight plan.
As far as I know it is not necessary to enter DCT between the geographic coordinates of a route.
You just need to separate the coordinates with a space. (space)
That’s the whole difficulty of asking an app to fill in a flight plan for us. So we risk errors because there are several conditions that apply depending on whether it’s an ATS route or not. How will the app tell the difference between the geographic coordinates of an ATS route and geographic coordinates outside ATS, and how will it decide whether to insert the term DCT or not?
How will it know whether to insert a change of heading or speed? Which also doesn’t require DCT.
I’m afraid that in trying to keep things simple we’ll head straight into complications
Personally I printed the latest known SERA notice (…?) and I send an ICAO-format file by email to the BRIA in Bordeaux. Then I call by phone because they don’t read emails right away. That way, once on the phone they have the paper in front of them in case of questions. I also bring blank forms that I fill in by hand in case I need to refile a flight plan during the trip (in case of a destination change, or a change for crossing a border, for example.)
Despite these precautions there are still input errors by the operator.
So doing it with an application seems even more uncertain to me.