I can only give my perspective, which is likely to be unique. I'm in the process of implementing an Oauth2 server for the first time. I feel like I have a handle on it now, but it was definitely overwhelming at first. If I were confident that RFC6749 had everything in it that I needed, I would read through and implement it. But it quickly became apparent that there are a dizzying array of RFCs with extensions, deletions, and best practices. So I just skipped the specs, and have been using resources like this, Oauth2 Simplified, and of course YouTube.
So I guess the upshot is I find resources like this and the upcoming 2.1 to be valuable.
So I guess the upshot is I find resources like this and the upcoming 2.1 to be valuable.