Excel has track changes, and Powerpoint can merge two different versions of a slideshow together. Word can do both, of course. Yes, it's slightly clunky, but q

Excel has track changes, and Powerpoint can merge two different versions of a slideshow together. Word can do both, of course. Yes, it's slightly clunky, but quite effective as long as you know how to use it: for example, you usually want to minimize unnecessary changes to formatting to make it easier to see differences, just like how you're not supposed to mix whitespace and code changes in a patch.