The most successful company I ever worked for (late 90's, the founder was a billionaire for a few months after the IPO, 99.9% of HN readers use an evolution of what we built every day) had a policy of rejecting any proposal for a tech feature or significant improvement unless it was properly documented.

We had a collection of templates for the types of documents we used. I could create a feature proposal in an hour or two, and the template ensured that all first-round questions were answered out of the box, saving many hours of staff time.

The tech founders set this up and forced everyone else to use it and once we saw the value, peer pressure kept it going. It worked incredibly well.

We weren't writing RFCs, but we had a doc process that respected (and saved) everyone's time and attention. That helped us move fast together. It really worked.