If I have an impress presentation that contains an SVG, I can save it to ODP and everything is fine. If I try to save the presentation as PPT or PPTX any embedded SVGs are replaced with low-resolution rasterized versions. It would be great if the PPTX file could have the embedded SVG contained in it (I think PPTX supports this now), but, at a minimum, the rasterized version should be of much higher quality.
I confirm this issue.
It should be possible to convert the SVGs in EMF images.
Or at least, use higher resolution rasterized images, as cyrus said.