I agree that how intellectual an anime is should be judged relative to other anime. But I'm still surprised no-one seriously suggested that anime is meant for kids (perhaps aside from the OP himself).

I know what you mean about looking for anime that doesn't fit the standard magical psychic samurai girls piloting mecha mold of anime. But if you're looking for anime which has none of the typical traits of anime then why don't you just look for something which isn't anime? You've said so yourself that the animation comes second in line, and the artwork in the anime which do break the mold is often not great because they rarely have the budget. Admittedly the flexibility of animation means you can get some fantastically bizarre looking creations, but in my experience these are generally fairly shallow, and their visual innovation is rarely matched by the plot or concept.