Chrono Cross was a game of it's own kind. But to me, it handed out more questions then it answered. As already mentioned by Beach Bum. Cross was not a closure. It's as if they intentionally bordered the entire story on the lines of Chrono Cross and carefully avoided answering any of the questions that were necessary in the the second instalment.
And if you really think about it, the ending of Cross is also VERY ambiguous. It's open to our interpretations but it never gives away a solid answer to what our actions have done.
Kind of like, here, you did this. Now think of what impact your choices made. Good luck!