I see there are some common ideas here but I wanted to add my two cents:
I think many agree his moveset needs to be updated. How about this:
- Forward Smash replaced with a hammer smash just like in all of the Mario RPG games.
- Up Special is Cappy, and functions a little like Ike's Aether in that Mario throws Cappy upwards (or it can be angled) dealing damage to anyone touching the spinning cap, and then Mario dives after it.
- Side Special remains Cape, but never turns someone to face Mario, only away. And, if you hold the button then Mario will continue spinning (which slows his fall) just like in Super Mario World (a lot of other reflectors can be held indefinitely anyway)
- Down Special remains FLUDD, but this time if you have a charge and use it in the air, Mario will use the Rocket Nozzle instead, which gives him an alternate recovery option
- Mario's expressions are not so angry but rather happy like he is in his games
I like the idea of his recovery being a barrel blast, and I think his neutral special could be replaced with Coconut Gun, which fires in spurts. Headbutt could be replaced with a different animation using his hands, since I don't think Donkey Kong ever headbutts in his games.
Definitely needs a rework.
- Forward Smash replaced with the Melee Counter attack from Samus Returns
- Down Special is now a toggle move that puts Samus in morph ball form. While in this form you can roll around and jump, dealing slight knockback to anyone like the dash attack ability. Pressing the attack button drops a bomb, which is not fiery but electrical. Pressing the special button again returns you to normal form. Morph Ball is also a bit larger like it is in most of the Metroid games, and her dodge roll is something else
- Up Special, Screw Attack, has a slight delay so that you can angle it more horizontally if desired, and it travels further (I mean come on it's the best move in her games)
- Neutral Special is now similar to Shulk's Monado Arts wheel, where you can select either Missiles, Power Beam, Wave Beam, or Ice Beam
- Side Special fires your arm cannon with whichever weapon you have selected. Missiles function about the same. Power Beam is weakest but fires the fastest, Wave Beam is slower but deals electrical damage and passes through opponents and walls, Ice Beam of course has a chance to freeze an opponent. Holding down the special button can still charge up a shot, but you can't store the charge.