For the first time in the series, Super Smash Bros. for Wii U allowed for up to 8 players in a single match. It was an awesome, heavily under rated feature and I personally believe it deserves a second shot. While the feature was incredibly hectic in free-for-alls or with more than two teams, I believe there's room for improvement and serious potential in 3v3 or 4v4.
One way I've thought about this is with an added option of a "tag" system, somewhat akin to Party Matches in Dragon Ball FighterZ. For an example, in a 4v4 match, only two players on each team would be active at a given time. The rest are invincible but can't do anything. The active players can tag their inactive teammates in, becoming inactive in the process. Imagine a transformation character, but with any combination of characters, and each "form" controlled by a separate player.
Even without any improvements, the mode is just plain fun in a less serious environment, and it makes Smash even better for big parties without needing too many copies of the game or complicated rotations. Of all the modes from previous Smash games, this is the one I'm hoping to see return the most.
Author's Note: Do you want this mode to return? Let us know in the comments below!