Well I mean where the entertainment is primarily within the drama, tension, or just in general plot and not the action.
I am using it very losely to the extent that the toddler show about oddly shaped robots is what I'd put as a "Drama"
Honestly I don't know if there's such a market within western animation
It is SOOO small that it is nearly nonexistant. Remember that most cartoons are made with the intent to sell merchandise and thus they, a lot of the time, go for lowest common denominator and thus in order to get funded they have to lay on either the action or the comedy really thick.
Which is why Avatar stands out as an exception because it is a recent action show that doesn't involve super heros (Thundercats being unpopular but one of them). In fact I highly believe that Avatar was what allowed non-superhero action shows to exist.
In fact you may not remember the non-stop comedies that occured once action shows, for some reason, started to become rather unpopular all of a sudden (I think it had something to do with copyright running out on certain super heros without being renewed). It was actually pretty bad and while many of the best shows came out around this time, it also KILLED variety. It is no wonder that Anime viewership started picking up again to fill in the slack.
After watching enough MLP though, I am willing to submit that it is indeed a Drama that makes heavy use of comedy because the plots are in the forefront and not the humor and the comedy is usually there to enhance the flow of movement that is already going on and not to detract from it like comedies tend to as well as having a strong focus on character, to a certain extent. It is rather unique in that regard. Mind you it could be considered an Adventure show, but I havn't seen enough of it.
For me I think what I kinda would like is more variety in cartoons in terms of genres without heavy saturation of comedy or action being required.