Try to define what constitutes 'good' animation and you are always going to end up stepping on too many toes, there are just too many factors to consider. Defining the rules for what constitutes 'rubbish' animation, however, is much easier - and I have reduced this process to the consideration of just two factors. Observe:
When creating animation, for one to produce work which can be defined as 'not rubbish', one must observe the following two rules. Failure to observe either one will result in animation which can be rightly identified as 'rubbish'.
Firstly, one must be in the same room as the animation for which one is responsible. Being in the same building is not sufficient, and being in a different postal district or hemisphere is right out.
Secondly, one must recognise that animation in all its forms concerns the creation of sequential imagery, and therefore consideration and attention must be paid to every frame! This does not mean that one must animate consistently on 1's - rather, it means that supervision be given to each frame, and that the amount of movement and nature of movement therein, be personally observed and considered. Attention to only key frames, or to key poses, shall equally result in 'rubbish' animation.
The first of those guidelines is self explanatory. Its a seemingly innocuous statement until you realise that it automatically discounts most TV animation and most Hollywood movies, as having rubbish animation. And rightly so.
Certainly you can make an entertaining show using outsourced animation, but you're simply not going to produce something that contributes anything dramatic to the animation lexicon. The entertainment value is going to derive from elsewhere, from the script or the direction. The animation is inherently going to be functional at best.
The second dictate however, is the more incendiary, as when applied to certain popular ongoing debates, can be used to burn a number of sacred cows.
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Now don't get me wrong, in certain respects its as beautiful as any other Otomo movie. It has nice backgrounds, good prop models and okay puppets - and sure, with a little more time and money you could tweak the physics, add more variety to the facial animation, put in more subtle moment-specific movements and it would be almost truly indistinguishable from a drawn animation. But in so doing, you would be taking the process so close to actual frame-by-frame animation, as to negate any economy generated from rendering it with puppets in the first place. In short, there are no effective shortcuts around that second golden rule!
Its clear that after spending a billion years making Steam Boy, that this is an experiment in economy film making for Otomo - which is fine. But is the soul behind the eyes of the characters really a fair or economic exchange for all those detailed costumes?
So there it is. Now in conclusion, lets see what it looks like when both rules are lovingly observed.