Relevant to the current discussion is this quote:
Quote
Ms. Maitland hated this, and was furious with Kubrick for insisting on it. ''It must have been a very strong visual thing for him,'' she says, ''because he wasn't usually stupid about story. He hired me because I knew about fairy stories, but would not listen when I told him, 'You can have a failed quest, but you can't have an achieved quest and no reward.' ''
I personally have no problem whatsoever with the ending. I actually like the sappy tragedy of the boy-robot achieving his quest the only way he knew how to: with pure, unspoiled, eery, unnatural, and almost super-human love.
To me it was always a story of "Can this robot really love?" Ultimately, that's all the robot can understand. A tragedy, and a strange victory.