Pretty sure it was intentional, they used the same voice actors for all of the characters who were in Shenmue 1 and 2 as far as I know, and it seems like they purposefully directed them to act the same way they did in the first two games, even if their voice acting skills have improved since then. Everything about this game was designed to be nostalgic and stay true to the originals. That being said, from what I've heard in trailers the English voice acting is definitely an improvement over the first 2 games, even Ryo got a bit better.
I'm not sure that's really a thing to be so nostalgic about that they should actively make their game worse. 20 years ago it was understandable and mostly expected in Japanese games, but if they are intentionally hampering their own game to appeal to some misguided feeling of nostalgia then I don't really know what to say. There are ways to do callbacks to the older games and use elements from them in a way that doesn't hurt the experience in the new game, and this really isn't it. Maybe it's just something that I don't understand since I have no emotional attachment to the first two games.