The character is the center of any great anime, at least as far as I am concerned.
This is one of several elements that separate anime from the plethora of western cartoons out there. The world of western animations is filled with ageless, immortal characters rising to challenge day after day of endless obstacles with never changing faces.
Well you cant really compare DC/Marvel comics to manga. Everybody got their own version of batman. Most DC/Marvel comics are for grown ups. Manga well the most popular manga are for kids. One Piece is for everybody thats like the only manga over there where the audience is like 30+.
Cartoons do have some good stories. Just like anime about 90% of cartoons is now crap.
I think the most obvious is the art and the seriousness of it plus cartoons are produced easier