We have, though it doesn't really go anywhere last couple of times it's been brought up. And I can see why--one is almost certainly Home-Run Contest. One other Smash mode, and then three online modes (the amount, says to me, some are offline modes going online). That would be interesting, except a) there's a possibility one or more of those modes were scrapped, and b) there are examples, like VR mode, where they add a numerical item. So we don't even have a min or max in terms of how many modes will come. I find it interesting for speculation, for myself, anyways.