Okay, I was so disappointed with Chapter 10 that I ploughed right on and did Chapter 11, and wow, more than made up for it.
I can't remember who is was (spemanig?) who commented that cutscene quality improves dramatically improves in the last two chapters, but for 11 at least, it definitely does. Music and direction are night and day better than prior story chapters. Boss difficulty was well balanced too, with no really irritating behaviours or abilities.
You know, while it may be less consistent overall, there really are times when XCX's core brilliance shines through so brightly that it can proudly stand alongside its legendary predecessor. I think if they'd had the time and money, the whole game would've had this level of attention, but the scope of the project ran got away from them a little bit, and they had to choose where best to invest their full efforts so that it didn't end up a money-haemorrhaging decade-long production.