If you're sensing that I'm sounding awefully apologetic, you've got it right. I recently watched a bit of Atom and once the nostalgia ran out, I found it boring. I know that I mention why I'm into anime quite often, so I'm sure you're sick of reading about why I'm so into anime. If you are, that's too bad. Think otaku that started Daicon, which later became Gainax. Remember what intrigued those otaku in Otaku no Video? Animation. Frames of giant robots, magical girls, and spaceships done in such a way that the details are in each frame instead of the movements. Smooth movements are cool, no doubt, but not when it's done to over-emphasize regular movements. In Metropolis, some scenes are very nicely done. For example, after Tima is awakened, she moves a bit awkwardly for a while. Her arms tend to swing about because she's not really controlling them constantly. That's some brilliant work. On the other hand, sometimes, it goes too far. It makes characters look like they're puppets on strings. It almost reminds me of recent Disney films. No, I take that back. It's surely not as bad as that. And you know what? One of the things that is important to otaku is the attractive character designs beyond just artistic level, but to a personal level. Why do you think people draw doujinshi and write fanfics? With the types of work like Atom and Metropolis, it's not as interesting, and maybe even impossible, to relate to the characters in such a fanciful way because the art style is, with all due respect, too catoonish. Perhaps due to this fact, I'm more fond of Matsumoto Leiji's works than Tezuka's works among the early anime works.
