@Lan Di-sama Your post reflects almost exactly how I feel about the 3rd game.
This. I don't even mind the structure of searching for Yuan per se, I think there was a way to do it well. But looking back at S2's ending I don't think anyone could be blamed for not thinking that he was alive. The ending very clearly implies that he is dead or at least gone. That's nothing to say that the whole ending with the cave reliefs, prophecy, the sword of seven stars, and "voices from the stone" were completely swept under the rug and likely never to be revisited again.
I think at some point I will re-play S3 but I want to wait a few years to go in with a blank state mind again. I'm curious to see what my takeaways will be and what I'll like more and less on the second pass.