There are some good and bad things about both ways of animation. 3D animation allows for more realistic animation and detail, although if it's meant to be used on a series, due to the tigh schedules probably the animators wouldn't have time to animate the characters right, and they would look "choppy" (have you seen that Starship Troopers animation series? That's what I'm talking about). Also, fluids and flexible objects (clothing, tree leaves, etc...) require a lot of time to make them look right. Anyway, if it was to be done in 3D, it would HAVE to be done in cel-mapping, cel-shadding, or whatever you want to call it (rendering 3D images in 2D with a black outline around all objects).
2D animation would have to be done right. There are way too many shows with awfully bad animation. Outside Japan, the best animators I know probably are Hanna-Barbera, but I don't know if Usagi matches his current cartoon style (thick lines, flat characters...). Disney would be another choice, but I'd mean having to sacrifice UY for a really lame fighting rabbit with some really lame one-liners (I'm not saying that I hate Disney, some of their movies are good, but all their series seriously suck). There's also Aardman (Chicken Run), but these guys work with clay

. Having UY in stop-motion would be kinda cool

.
I loved the Animatrix! My favourite was #7, "Beyond". There's something really special about that one, although I don't know how to explain it

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