I’ve been trying to export an Omnioutliner document to Keynote. (Note I searched the forums but could not find anything recent on this). When I export it to .pptx it puts the whole outline on one slide. I also tried this script
Both the PowerPoint export and Keynote script work the same way in that is creates a new slide for each level 1 row. I suspect something changed with Keynote’s AppleScript support that broke that part of the script though. You’ll need to modify your OmniOutliner file accordingly to make use of either. You can do so by selecting the level 1 row and using Organize > Ungroup. Hope this helps!
Maybe something has changed since your post, but I was just playing around with this today. It seems to me that the script hangs if I try to run it with Keynote open, but works (so far, anyway, every time) when I have Keynote closed. I’m not sure what difference that would make to simply running the get theme script, but maybe knowing this would help.