I don't think Dave is suggesting that a 'good stroke' or stroke that can be defined as good (e.g. repeatable, delivering to the required specification) is not imperative. A 'good stroke' can look like shit, as long as it delivers all of the necessary requirements to the Cue ball. The stroke is simply the vessel which delivers all of the things Dave suggested... Physics... 'science bitchhh'

(edit: not calling you a bitch, just quoting a show haha)
So Dave is right, Your stroke could look like utter shit, as long as it delivers the required necessities for doing what it is you intend to do with the ball, it is a 'good stroke'
There are of course methods which give the desired results more often than others, and these usually become copied and evolve into a 'gold standard' or correct method that is then coached or fawned over as being a 'perfect' stroke - Snooker coaching is prime example of this. Cue action and what that looks like, is drilled into young players, and there is not much variation with what is considered 'best practice'.
It absolutely bewildered me how some of the ugliest and most ungainly styles were actually effective methods for winning games of pool.