* not comics: the cartoonist Colleen Doran has learned the art of making blog posts while walking via moving a part of her work day to a desk/treadmill. She also refers to herself as a "web-addicted pudding woman," which is hilarious no matter how much one might protest. Stan Lee wrote while standing up for at least part of his career, and God willing he turns 90 this year. He has more energy at conventions than three 30-year-olds. So there's gotta be something to this.
* finally, I think the question here may be less about a character being boring than any character at all being able to sustain weekly stories for 75 years or whatever Superman has to its credit at this point, all while wrapped up in a specific set of story expectations that needs to be maintained almost exactly as is so that the character can be sold to other media whenever the opportunity arises. That's tough, even when your character is awesome. No one was really meant to read these characters for decades and decades on end.