Requirements revision review. It is the most mind-numbing part of my job and fortunately only a small portion of it.
A word changes, even just punctuation changes, can change the meaning drastically. And finding that change within a hundred page document is a task humans just plain suck at. Get a computer to compare revision A to revision B, highlight the changes, then pass it on to the human to interpret the change and decide what to do from there.
Comparing version A to version B and highlighting the changes is already something software can do, so I hope that you're already aware of this. But if you're not, just know that it's out there! Lol