Yeah to me I'm hoping we look back on this game in 5-6 years in about the same way we (well, I should probably say "I") look back on Shenmue 1. There's a lot of novelty but the lightness in story will make it feel like it's a tech demo in the grand scheme.
I think that part of the disappointment is that it feels like it's actively not trying to advance the story.
I got the game after knowing that a lot of people were disappointed by the story, and after 1 hour I was already anticipating that we wouldn't find Yuan till the end. But there was a lack of anything substantial inbetween.
It does sting more, because they got SO MANY things right, but fumbled a part that should be about the writing and not about budget (though I think that the training with masters sequences might have been cut off due to budget).
I might not disagree with the story of the first one being one big redherring, but you get a lot of info in the game, you learn that the mirrors were made in guilin, all the basic story about Lan Di thinking Iwao killed his father, learn about the chi you men, learn about the prophecy of the dragon and phoenix, learn about the hazuki crest, learn that you father travelled to china, get a general understanding of Ryo's present and past.
Even in the stuff that doesn't advance the story, like "finding chinese people" you get a nice tidbit about the three blades, or showing the mirrors to different people they give tidbits about chinese culture (and compare that to what would be a side quest in S3), or background on characters / the world.
And even if by analyzing the game on retrospective you understand that all you "really" do is finding master chen and he gives you the knowledge about the mirrors and Lan Di location, while I was playing the game I really never noticed that and felt like I was doing continuous advance. In Shenmue 3 you spend the whole game trying to find Yuan and some "thugs" and not even the "thugs" are developed in any way.
I don't think it's just from a fan perspective trying to get info about a story that has been lingering 18 years in my mind, I stumbled about this video (by the title I thought it was going to be more positive):
At 6:50 he says what he thinks about the story, and he doesn't seem to be a fan, so it's not like he's invested in finding out the "big plot", and it was how I was feeling the whole time (hell, even after you reach Niaowu you are still trying to find "thugs").
PD. HELL I just was refreshing my memory and I watched the bunkado antiques cutscene and he even tells you that an emperor ordered a sculptor from guilin to engrave a guardian on stone.