Events are majors or they aren't, and I don't think it makes sense to gauge solely by the competition. There isn't any core criteria for whether a game is a major or not right now, but consider this: CEO is universally agreed to be a major. This year, two of the Marvel gods couldn't make it. Is it still a Marvel major?
If an event is dependent on the level of competition for its title, then any time the Marvel gods don't show up, the event loses its status as a major. Doesn't that seem odd to you? Since ZeRo is the only real high level player in Smash 4, any event he doesn't show up to is no longer a major, either.
Majors are majors, IMO, because of the crowds they draw. Even if no top players show up to an event, if it has a 512 player bracket, I think it can be called a major based on draw alone. If it is based on competition, then we have to call something like a 16 player tournament a "major" if the best players show up, and that is pretty ridiculous.