Maybe complain is not the right word. I would have to look it up. He mentions on the DVDs that he thinks Universal should have promoted the 2nd and 3rd film differently. Also that the Part III's box office was hurt by such a short window. That a year wait would have been better.
I love the ending of Part II as well. I remember as I kid when I heard they were making a Part III right away, I had the idea that both would be shown at the same time.