Malos
I can already see Twitter complaining about another anime swordsman being added to Smash. Still, he would be one of the easiest characters to move from the Xenoblade Chronicles universe into Smash Bros. He would also be the first villain from the franchise to make it onto the roster.
I could see Malos having a similar moveset to Shulk for physical attacks and when it comes to using down b to change Monado arts. However, the arts themselves would be mostly different than what Shulk has. The only similarities would be the buster and armor arts.
I could see him ending up being one of those characters like Dr. Mario where he’s very close to being an echo fighter. But there would be enough of a difference between the Monado arts and other special moves to keep Malos as his own character.