Just looking at a few of the slides there, and the fact that it's Shay presenting, I'm going to go out on a limb here and state that while many of the principles in here remain true, some of them are no longer true, and we're giving different advice. This is mostly due to the fact that Lucene has changed much since this talk, and many of the reasons we did things the way we did were to work around things that have been updated/fixed/changed (in Lucene), and no longer apply.
My recommendation: Get up-to-date recommendations from the Elasticsearch team before latching on to potentially outdated material.