You've hit it right in the head. The gameplay was far from the focus of praise ironically it was getting. It was more about the story, the companionship and ND's testament of pacing that was resonated amongst reviews and gamers alike. Which is why it is not surprising to see "gameplay" was hardly extrapolated because - at best - is a competent game among the generic formula titles have been released.
But that discussion always end up awry because of its inherent flaws - in this case, the AI. While at the fundamental "gameplay" level; it works, challenging the player mechanics by the least. But the nerfed design of said AI of not capable of observing your partner(s) really heightened the dissonant effect, considering the story and journey was perfectly consistent throughout.
What makes matters even more complicated was that the original gameplay reveal never showcased such flaws; the AI was far more reactive and there was nothing to indicate the same dissonant effect we see at the final game. It was consistent, it escalated the tension to unprecedented levels. Gamers were talking about the reveal gameplay more than the actual gameplay of the final product. That is a very telling evaluation, regardless of how it was received.
You can't (and won't) substantiate any of this. I see no evidence of any of the following:
1. The gameplay was not a major focus of praise the game was receiving, either from the media or the forum (N.B. I just read all of the review summaries on the Metacritic).
Please explain what it means for "gameplay to be hardly extrapolated".
2. Please prove the AI was nerfed. I've asked two other posters to do this in the past and they have both backed off the claim when pressed. I'd love to see you actually demonstrate this as being true.
Additionally, the AI observing your partners and entering an alert status would have been bad game design. That would have been incredibly frustrating and would have punished players for behaviors outside of their control.
3. Please prove that gamers were talking about the reveal gameplay after the actual game was out and/or continue to do so.
The scene in that original reveal is one of the more linear (that is, rectangular) setpieces in the game. The player is just with one companion (as opposed to three) who stays hidden at all times. Ellie does this in that location in the final product. It is not analogous to some of the other environments throughout the game where Joel is accompanied by two or more AI partners that are actively moving through larger environments.
You can't just say stuff like this and expect it to go unchallenged, particularly when you argue, as you have, that it is a merely "competent" game. Talk about damning with faint praise.
The point is that neither of you have hit anything on the head except for squarely codifying your perception of an incredible amount of praise as oriented in a particular fashion or angled in a particular way. Look at Neff's quote: "...the zealous praise for this game doesn't seem terribly steeped in the gameplay..." Sure, if you don't want it to be the case. This is called confirmation bias. Sorry, it's demonstrably false.