Unless I'm missing something (using a script blocker, though SE is on the whitelist), navigation in a slideshow always goes one slide at a time. Which of course how you would read it if you're reading it for the first time.
However, I often find myself wanting to refer back to a specific slide and then having to click through a bunch of slides just to get to the one I want. Some of the slideshows are short, but for longer ones (like the Burger Bash one), it's very tedious to click so much.
I think it would be useful if there was a drop down menu where you could select the slide you want to get to or perhaps a text field where you could type a number and get to that slide.
Even better (though more labor intensive) would be if there were gallery of thumbnails of the slides so you could see what you want (vs just guessing what slide it was with the above methods).