I largely stick to western because Japanese games to be saturated with tags I avoid.
I think a lot of the standout features of Japanese games are as you mention is they more or less come out completed and/or have a clear end goal/vision for where the game is going, but say they are on rpgm, they usually take full advantage and add gameplay elements that make sense. On the other hand with its a straight VN they typically go pretty much straight into the porn with little buildup. The main weaknesses I see are they largely have a lot of the same tropes, samey writing, pretty misogynistic, lots of incel leanings and fantasies like getting cuckolded and the aforementioned misogyny/rape and again tons of tags I usually avoid.
Western games tend to suffer a lot of the inverse, the games often stall for years, devs have no clear end goal or vision, try to fit too many hats and put tags that are diametrically opposed or end up doubling their work if they want to do it right and make a true opposite path. But in terms of strength, obv depends on the dev but the dialogue tends to be better, more use of relationships/building, typically tend to be 3d instead of pixel/2d, though that can vary as well.