Does there have to be a happy ending? At least it was ambitious.
Not necessarily, though that's what many Americans seem to want. But a good one would have been nice. At least two of those other three endings would have been a much better place to stop the movie (tossing out the child once the real child was cured and sitting in front of the statue under the sea) than the horribly muddled and unsatisfied ending that the movie mercifully stopped with.
I'm curious, though. On what ground do you consider it "ambitious"?