I guess when you put it that way, it makes sense. Quality vs quantity... But, it also depends on the writing. Which a lot of people say that the writing in Genshin is bad or something. I disagree on this point, though.
I do feel like if Traveller didn't show up Inazuma would have still progressed more or less the same, but that's just my opinion.
Although for Mondstadt & Liyue, I was fine with those being shorter since both didn't have like government and politics involved, you know?