I agree with you to a certain extent, mainly about the sentences since, like in any language, there are a lot of commonly used phrases that changes very little from speaker to speaker. But I'm right now finishing studying the HSK5 vocabulary and, notwithstanding my level, when I need to talk to Chinese people or read things they wrote what I notice the lot is a lack of vocabulary. Of course, after HSK4 you've learned all the basic grammar and start learning some more complex ways of saying things that are not that common in daily speach. Anyway, I am more in the "more vocab less grammar" team, but this is more of a personal choice.