You know, that's a good question. I have a feeling that, to those devoted to sci-fi, the biggest allure is the hardware (the ships, weaponry, etc.) and in order for those to be the most believeable, they have to be either live-action or rendered in 3D. 2D animation, no matter smooth and accomplished, doesn't cut it in that regard. And you know, it's a shame. Recently I've acquired a new respect for the sci-fi toon Treasure Planet. It is damn beautiful to look at, and some of the characters, such as the doggy doctor, the catty ship captain, and especially the cyborg Long John Silver, are terrific. But the movie was a flop. And I think it's just one in a long line of sci-fi toon flops. I hope the new Astro Boy doesn't suffer the same fate just because it's sci-fi. Not to mention Wall*E (although of course the Pixar name will probably win even the most ardent sci-fi fans over). 2D animation seems better suited to bringing fantasy characters to life than in creating sci-fi worlds. Weird, but there it is.