Personally, I would rather see Frogger playable. On the surface, he may not seem like a fighter with potential, but if you craft a moveset based on the gameplay, you can get a really unique character out of Frogger, sorta like Pac-Man in a sense. I made a short moveset months ago, detailing what kind of playstyle he could have here:
Moveset and Playstyle
Neutral-B: Tongue Lash: Frogger quickly whips out his tongue to paralyze the opponent for a very short period of time that allows Frogger to attack freely. The tongue automatically homes at the opponent within its area. Can be rapidly used to paralyze multiple opponents. If abused too much, Frogger tires out and is vulnerable to attack.
Side-B: Thrust Jump: Frogger leans charges for a horizontal spin jump attack. The longer you charge, the greater the distance. When the move is active, Frogger can dodge by pressing the special button, and pressing B again allows Frogger to do a quick, but weak counterattack. If abused too much, Frogger tires out and is vulnerable to attack.
Down-B: Vehicle: Frogger summons a vehicle, avoiding the vehicle by jumping from behind. These vehicles range from powerful to weak: trucks, cars, buses, motorcycles, bicycles. The vehicle chosen is randomized. If Frogger is tired out when using this move, Frogger will end up being hit by the vehicle.
Up-B: High-Jump: Functions similarly Thrust Jump. You can jump a high vertical distance, spin-jump attack, be able to dodge in mid-air, and counter too. The special move does not have the weakness of tiring Frogger out, but if Frogger uses this move while in a tired state from using Neutral-B, the vertical distance travelled will be far lower.
Frogger would basically be an evading master in Smash, staying true to how Frogger plays in the arcade game. He can dodge-roll quickly, side-step quickly, a plethora of moves that help Frogger escape from the most tight situations. When Frogger successfully avoids an attack from an opponent, he is awarded stamina, which recovers his special moves back to its normal state. The weaknesses he would have is his weak attack power, being VERY lightweight, and being able to tire out if Frogger uses his special moves too much. In return, he is a character with masterful mobility. If I could name his play-style, he would be called the "Evasive Martial Artist".
I want to see two of the biggest third-party arcade mascots in Smash Ultimate!