Guild: Interesting point on Calvin and one I hadn't thought of.
Regarding the Simpsons' hairstyles: Groening has said that he wanted them all recognizable in silhouette (like Fred Flintstone or Bullwinkle). Lisa's hair has ten points viewed straight-on, which it almost never is; in the standard 3/4 view you see eight of them. (In three dimensions, of course, she has more.)
The 3/4 view is typical of most cartoons and comics. Off the top of my head I think the newspaper "funnies" tend to be an exception; you frequently see Charlie Brown or Calvin either straight-on or in full profile. (In fact I believe a "3/4 view" in Peanuts consists of Chuck facing the viewer while his body is shown in profile. I think I saw somebody do a full rotation animation of Charlie Brown's head recently; it was weird.)
I can't quite picture Calvin in 3D, and Charlie Brown in 3D looks a lot like a face drawn on a balloon. You're right that Tintin is easier to picture in 3D, but that's not the same thing as mocap; I'd be much more comfortable with a CG movie that hewed closer to Herge's style than GIANT CG PORES.
I'm certainly not opposed to CG movies (though I'd rather see more traditional animation), and I'm not opposed to mocap; Peter Jackson and Andy Serkis have more than proven themselves on that score. But I've yet to see a fully-mocap movie that really justified its existence as fully-mocap. It strikes me that mocap is best for sticking CG characters in live-action movies, and that building an entire movie out of it produces an unsatisfying middle-ground between cartoonish CG and fantastic live-action.
And of course 3D effects CAN be pulled off in hand-drawn animation -- some of the most impressive sequences Simpsons have ever done have rotated the "camera" around a character (like when Homer's mom becomes a hippie).
And again, the original Akira movie is just one of the most gorgeous examples of hand-drawn animation you're ever going to see. Lazy trolls can dismiss it for being an incoherent mess stretched out over an unoriginal premise, but that's not the goddamn point; the point is that it pushed the absolute limits of what its visual medium (media, really, since this goes for the manga too) is capable of.