As the end of the first season approached I had two wishes:
1) I want more of this above all, but--
2) -- when it's time for an ending, do not fuck up the ending. Ultimately Ciel has to die.
The series gave us option number two, and gave it perfectly. Ciel, through the series, never shied from his duty or his fate. A debt was owed, Ciel meant to pay it, and never thought of cheating his death or his demon.
And no, the ending was not ambiguous. The entire second half of the last episode lays Ciel to rest; even for the "Don't believe it until you see the body" rule of adventure fiction, we got to see the body every damn time the end credits rolled for ten episodes. The intent is there, even if we don't actually get to see Sebastian chewing.
And now the announcement of a second season. Guys, I've decided I'm going to be happy about this. I love this series, despite its flaws; as odd and confusing as some of the episodes became, the characters are riveting. It isn't a jewel of coherent storytelling like Death Note or Code Geass, but I wanted as many stories about Ciel and Sebastian as this series agreed to churn out, because they're delicious, and peripheral characters such as Undertaker and Grell and Pluto are cracked-out eye-candy to flesh this mad thing out.
Possibly the second season will not contradict the ending of the first. Ideally we'll get a series of insert mysteries that fill the spaces between the other stories; even if that doesn't happen, well, I have had all the emotional impact of the ending of the first season, and no one can take that from me. The authorial intention seems too explicit, from the ending of season one: we were meant to have the emotional effect that Ciel died. So I can look at anything that occurs post-ending as fanfiction, if I want, and enjoy the hell out of it, and just be happy that Kuroshitsuji has proved to be so popular that the demand for more can't be ignored.