I feel like Gooigi could work amazing as something like Dark Samus; Mostly the same as the original fighter, but has an array of unique animations/attack properties so that there's actual reason for him to get in Daisy and Richter always make me wince. Maybe Gooigi could shoot a reskinned fireball that uses the data from Smash 4's ice ball? But instead of freeze, it covers you in "goo" (basically inkling ink)? Other moves could be based on Floating Missile (makes sense because he's goo), Burial Header and Mach Cyclone (but nerfed a little, that move would basically make Gooigi have a way better recovery than Luigi lmao).