didn't notice that at all when we were there a couple of weeks ago. We only saw Dicken's, but the sound was as good as it normally is. I'm particularly annoyed when instruments drown out vocals, but didn't notice that being a problem when we saw it.
Maybe a couple of new sound techs they were training? Don't ask me why, but it seems like it's typically the young guys that get the balance mix backwards when it comes to music vs. voice and drown out the vocals. Not always, but more often that way than the other.