Maybe the OP meant something else, but for me writing less is about getting rid of the fluff in non-fiction books. It feels like large portions of those are marketing materials for themselves, telling me how great this book is going to be. Is buyer's remorse this strong that the authors need to alleviate it?

Getting Things Done is the most notorious example from my recent reading list.

I noticed other readers also dislike different anecdotes talking about the same idea. I see how repetition is helpful in learning, so it doesn't bother me as much. But I guess you could trim some fat here too.

“[…] of making many books there is no end; and much study is a weariness of the flesh. ”

— Ecclesiastes 12:12