With the logic I added to check for circle shaped polygons and converting them to QET ellipses hopefully this will be less of an issue, but I know there is more work to be done here.
The circle was just one example: it is also about other graphic elements, such as arcs. In many cases, text and the manufacturer's logo are composed of many individual polygons, too.
I doubt people will be importing dxf's of tiny simple drawings like a ladder diagram coil or contact. This would probably be mostly used for importing drawings of real life objects.
I agree: drawings converted from dxf are more likely to be used in the professional sector for front views (thumbnails). In my opinion, circuit diagram symbols represent the function schematically and do not look like the real part.
I would therefore refer to front views rather than schematic symbols for the conversion. And here we are not talking about small components with which an electronic circuit is built: That's what you make circuit boards for with KiCad!
We are talking about parts that are used in a domestic installation or in a control cabinet. I consider a size of 20x20mm (results in 40x40px) to be “small”: So we could also assume, for example, 50px as the minimum size, for which there would then be no need for extra scaling.
From my testing so far there are some issues with the placement of the text due to a bigger boundary box in QET (...)
As predicted 
:
You will have "a lot of fun” with the text position, (...)