The original note, as written at the time
Think, how do I jump, in the easiest way possible, to the right slide in my very huge presentation when I really need to do so?
Ongoing development
How do I get to the right slide in a very large presentation, in the easiest way possible, when I really need to?
It is a small question with a large answer, because a presentation of two hundred slides is a database with no query interface. The only navigation is next, back, and a grid of thumbnails so small that the titles are unreadable.
What is needed is search. Type three words and land on the slide. That alone would fix most of the problem, and it is trivially achievable — every deck already contains its own text.
The second need is structural. Presenters think in sections, so the deck should have named sections and a way to jump between them, and the sections should be visible in the speaker view but not on the projector.
The third is the one nobody builds: a memory of where you have been. In a long deck you return to the same four slides repeatedly, and the software should notice and offer them. That is a list of the four most useful buttons in the application and it is generated automatically.
The reason none of this exists is that presentation software was designed when a deck was twelve slides and the constraints were visual. A deck of two hundred is a different artefact — closer to a document than a poster — and the tooling never caught up.
The worst outcome is what we have: a presenter scrolling frantically in front of an audience while the projector shows the scroll.
If the deck is too big to navigate, the interface has failed, not the presenter.