PDF can work really well. Prevents transitions and less worries about compatibility on the presenting machine.
Plus, PDFs can be generated from Powerpoint.
The real key would be for some App to codify good presentation rules and target OOXML output. I'm not talking Keynote - It needs to be more focused and opinionated, and make that part easier.
Is that even possible? Would Microsoft permit it to exist?
You generate your PDF presentation from LaTeX, which is stored in git! Multiple simultaneous editors with sane merging, unlike a group of people editing a PPT file on the network drive.
But those are probably not the PDF presenters you're talking about.
Now you run into the WYSIWYG issue, where the collaboration format needs to be "printed" in order to see the output.
Is there a WYSIWIG collaboration tool for LaTeX over git?
Which I can now imagine someone doing. Gross.
PDF would not be the main format but it works well to export to that from powerpoint (or whatever) before presentation.
Wish it had ooxml support.