Just the section on how to rewrite alone communicates something incredibly valuable that grumpy-engineers like myself have great trouble getting others to understand.

I don't have my mind made-up on XP, I've never worked at a place that actually supported collaboration (often workers spoke different first languages, vastly different experience levels, had minimal social graces, were uncomfortable asking questions), but I think it could exist with great effort and would have a lot of upsides.