Except with some things the canon is so broad that you have to put limits in, otherwise, the concept has no meaning. For example, Link vs Batman, who wins? The answer depends on which Link and which Batman we are referring to. Majora's Mask Link will own Batman, every Batman, with an unlimited amount of prep time, because Link's powers can't be researched, codified and negated through careful preparations. Triforce of the Gods (A Link to the Past in America) Link? Not so much. Depending on which Batman we're talking about, his tactics, weapons of choice and gadgets available are very different.
Hell sometimes limitations are placed so as clarify where in the Manga the Author is. I'm currently at chapter 24 of a manga called Kurohime, but am up to date with Mahou Sensei Negima (chapter 260). Who would win: Negi from as far as I've read, or Kurohime from as far as I've read?
Good Limitations limit the character to one canonical moveset or the point at which the author of the thread knows and are necessary. Bad limitations effectively tie one character's hands so they can't win making the argument pointless.