Canaria Child was a surprisingly complex story, given its length. I'd have to disagree that it was a lame story that didn't make sense and centered too much on the two main characters; I think Hermit-chan and Molenir completely missed the point.
Firstly, the characters. The author made the correct choice in focusing entirely on Mitsuki, Yue, and Kotoi in the later chapters. Given the psychological damage that Mitsuki suffered when she found out her father's secret, and both her and Yue's inner conflicts as they tried to come to terms with reality, there was no way the author could've introduced all these other characters. They would've felt totally underdeveloped.
Secondly, the plot. In the whole story, Mitsuki and Yue are coming to terms...
...with the fact that they both have doll parts. They're afraid that they'll slowly become dolls, and they're not sure what makes them human and what makes them doll anymore, since dolls can be imbued with the owner's wishes and seem to come to life. There have been other manga, movies, TV shows, etc., exploring this difference. It's hardly a stupid idea.
The fact that dolls can be made to move and speak has blurred the lines between what is truly human and human-made - the collectors all bidding for a "living doll" isn't just something out of the blue. What they discover to be the one thing that makes them human is intriguing.
Thirdly, the art was very, very pretty. It kind of reminded me of Kaori Yuki's, for some reason, but less dark. My only complaint is that Yue and Kotoi looked remarkably similar when Yue had his glasses off; I had difficulty telling them apart in the last chapter.
All in all, I liked this far more than I thought I would. The doll theme was interesting rather than freaky, the idea of what separates the human and the doll was well-explored, given the short length, and the ending was quite satisfactory. Give this a go; don't let the previous comments discourage you.