Hi.
As far as I'm concerned you are quite out of luck with the problem.
Because by the underlying vector structure "what you see" is NOT what's rendered -"what you get"- on screen -hence it's not wysiwyg at first place.
The outlines only view is what really is wysiwyg.
Probably there is not a trivial solution that could solve the problem by an algorithm. There could be alot of different other parametres like the involvement of clipping, pattern fills etc.
The only solution I can think of may or may not suit your needs and also needs testing&some precaution.
The process is: underlying vectors--->rendering to screen pixels--->tracing the raster image back to vectors.
So at first it'd need the images exported as raster images at the highest possible (or one that "fits") resolution, with each stroke rendered with a hairline. There is a style setting in the svg to achieve the latter; I would need to look that up, not sure about the exact name.
Then, you would need to set up a centerline tracing process. Inkscape doesn't have one centerline tracer built in by default, although I remember there is some extension for it you can add custom?
Trace the raster image and you'd end up with something close.
As it all depends on the algorithm of the tracer, how it deciphers crossing lines or structures the geometry/topology; how many nodes it would add on a curve etc.
A high number of nodes may capture all the small quirks the original images had but they may not be so necessary everywhere.
If too many, they could halt the performance when working further on the traced images -needs testing of the original export resolution.
(Actually as it's for cad use, as a purist's note: Béziers are never exact after a cut, so even if it was possible at first place to "flatten" your image it wouldn't be a 100% match, just a 99,999999%.)
