Well size was the issue for PDF, PPT is still too big and not WYSIWYG (font issues, as Mac fonts are called in and replaced by the nearest font), Quicktime too big still. I mean respectively 57, 27 or 19 Mb for a 1.5Mb original file! And no, I cannot use iWork for iCloud, this is corporate content which cannot leave the company's network.
I am wondering what the resolution for PDF export is in dpi.
Considering that the image on the projector or someone else's screen will only typically reach 92 dpi (not sure what my Mac's screen size is in pixels, the typical PC screen is 1400-1600 something wide), print 150dpi (full page print), rasterizing need not go higher than this to be efficient ; most presentation paper printouts are done half page so even 75dpi could still do the trick.
Maybe the fonts are "convert to curves" instead of a more efficient "include fonts as subset". My presentation used a template from Keynote with a repeated image, I assume Keynote ("Exhibition") so I suppose Keynote internally reuses the image and thus keeps the size low.
Adobe InDesign offers many options to tweak PDF export, but as PDF does not support animations either, I would say my best workaround is export to images (all font issues solved, perfect WYSIWYG), play images from the image folder, and zip the images to a single file if I need to share it on a file server. Windows or Linux users are also covered (I was not thinking about the penguins at first but it also works for them so everyone is happy... )