Well I still feel like each game has their own niche though. I don't think Shenmue is that much worse, it was just doing something different.Pretty much that ^.
The original Shenmue is an amazingly groundbreaking experimental video game, and there's a lot to like about it.
The sequel is just magnitudes better though. It has more of a proper game structure, the systems are refined and expanded upon, the game world is bigger and more varied, and the story, characters, and pacing are, IMO, possibly the best I've ever seen in a video game.
Like Shenmue was fantastic because of how surprisingly believable the world was. Ryo knew a lot of the locals, and the dialogue would change depending on how far into the game you were. Like some of the locals had their own stories to tell. It also didn't matter that the pace was slow since it was very much an introduction story.
Shenmue 2 kind of lost that sense due to the scale, but the scale and the fact the tone had been set allowed for a brisker pace. Ryo had actually set off on his journey and it ends up being... more exciting as a result.