Before I start my textual rambling, I'd like you to watch these animations:
You might dislike this animation for it's simplicity, or you might love it for it. Or perhaps you don't really care. Maybe you saw a underlying message, satirical or political. Personally, I think it's brilliant.
Obviously, I'm trying to create a contrast and I might have gone a bit overboard, but I think The Proud Family is a perfect example for what I'm about to explain. You don't have to watch part 2, though.
At the beginning of development of my latest animated short film, Antumbra, my teacher showed us Lapsus. Like some of you, not all my classmates could appreciate it. They thought it was too simple and short, on which my teach responded: "It's incredibly simple, yes, but for such a simple animation, it tells a grand story! It's impossible to recreate this story in live-action, 3D or anything. This animation makes use of it's medium."
Ever since that day, I've been looking at animation in a different way. Not that I have drastically shifted my preferences, but now I have a better way to define it. It's like suddenly remembering the name of an old classmate, or the origin of that strange smell in your kitchen.
Now, let's look at The Proud Family. It's an animated sitcom, really. Same cast, same artwork, same jokes. The sitcom concept really fits an animated series for a commercial network, since you can reuse everything. But, because of it's 'sitcomness' this series could easily be translated to a live-action series. It does not make use of the medium.
Animators tell their story visually. Most independent animated short films don't have dialogue, especially in Europe. In Lapsus, the story is told by the nun's physical struggle between the white and black realm, while dialogue leads the narrative in The Proud Family. If you'd close your eyes while paying the video, you'd still be able to make sense of the story, just by listening to the audio.
There is no right or wrong in this case. People enjoy both worlds, which is fine. However, as an animator, I feel I should use my medium wisely, make animations worthy of their name. Sometimes it means discovering a small visual gag and creating a whole story around it, or trying to tell a story by only using a certain array of shapes. Let the colours speak, not the mouth.