Great concept (shoutout to Deckset and Slideas for tackling it earlier) and iA Presenter seems to be the one that's closer to get things right. That's great.
However, I hate this design-snobbish notion that every presentation is a story and a TED-talk/Apple Keynote. Not all presentations are a story, some are an update across multiple items, require complex and filled slides.
So, to fully use this I need:
1. Full custom layout for slides supporting titles, subtitles, page numbers, etc.
2. Grouping slides by chapter (the indentation tree seems to work)
3. Hiding slides
4. Collaboration via commenting
Hope this will be added for me to ditch Keynote and Google Slides.