The reason I restricted it to a single facet of their game (their scoring efficiency) is A. Because he specifically used that as an example in his question and B. I did not feel like taking literal hours to breakdown their entire game considering how much effort it took into breaking down a single facet of their game and all the variables that entails.
So you ask a lot of good questions, and many of those questions can be answered through statistical analysis. But you will ignore the statistical analysis so I won't bother going through all that work to show you as I did for Warfelg since he actually seems interested in learning. But consider the alternative option to some of your questions:
How do they fare against tougher competition? Well statistics could show you a breakdown of how they played against Top 5 defenses, or against top defensive players who guarded them. But you want to ignore that and use your subjective evaluation to determine who they played that was good and how they did against those players and teams. Which one do you think is more likely to yield results? The one based on pure opinion or the one based on objective data?
And this can be applied to pretty much all the questions you asked. How does either player restrict a gameplan? Every team in the NBA is using analytics to tell them that. literally every one. You don't think they broke down analytically how Westbrook and Harden played and how it impacted their offensive and defensive sets in order to determine the best way to use them? You think they decided to go small because the coach was of the opinion that would work as opposed to looking at the data that told him the team's offense did far better when it had more spacing and less size to accommodate Westbrook's drives and lack of shooting while not suffering a debilitating drop in defensive efficiency due to Tucker's versatility?
Do you honestly believe those kinds of decisions are made without any data?
To go back to your accusation of me ignoring the initial question, I would spend a lot of time in answering and coming to a conclusion based on objective data. You would simply go "NBA suckz now, back then was better, AI would totally pwn" while having put 0 thought into the question.
So whose method deserves criticism here?