My idea for a sonic moveset:
Down B - Still Spin Dash but requires tapping to B charge rather than holding and will do small damage on contact during said charge.
Forward B - Sonic Wind. Sonic would run in a quick loop, generating a small whirlwind which would then travel forward for just over a stagebuilder block's length, doing damage to anything it touches or causing weird wind properties on anything above. This references his special move from SA2 multiplayer and his comic book abilities, where he was able to generate tornadoes by running in circles.
Neutral B - Homing attack would keep the current startup spin, during which directional input could be made. If there is a target in that vague direction, sonic will head straight (not in an arc) for it with better accuracy than before. If there isn't, he will simply fly straight in that direction. Inputting would end the spin quicker, meaning lack of input would only be beneficial when you couldn't see the opponent and needed auto targeting to find them. Untargeted homing attacks travel shorter distances.
Up B - Light Dash. Sonic throws a ring up (and forward/backward), then light dashes to it in spinning ball form like in Sonic Battle. The input can be held to delay the dash part. The ring will do minimal damage if it collides with an opponent or heal if caught/picked up, either of which will stop the dash instantly. If Sonic hasn't started the dash, he will return to his pre-move action with a little delay. If he has and is on the ground, he will have a fair bit of delay in standing up (almost as much as when floored). Or if he's in the air, he will transition into a special fall state where he keeps the spin. After the initial transition lag, he will be able to move and attack as normal but his fall animation will maintain the spin if no attack or dodge is activated. During this animation, he will do a tiny amount of damage to anything he hits. This hitbox should be easily beaten out by anything. The actual Light Dash should be quite strong, given the drawbacks. Can be angled for more or less of a forward/backward part to the throw trajectory.
Dash Attack - The modern Dash. I don't like the dash but nor am I a fan of using generic spins for every move. Should work like a faster version of Kirby's Fireball except, you know, good.
Neutral A, A, A - Punch, Punch Kick. A reference to his basic moves in his only real fighting game. They may be pretty dull but they're also staples and I see no need to change them.
Dtilt - Slide Kick. This move is becoming very common in modern games. I'm not too fond of it but it does the job here. It's a basic low kick that slides based on how fast you are going prior to its activation.
Ftilt - Horse Kick. This feels more like a smash than a tilt but his real smash does even more so and it's not a bad move. No changes here.
Utilt - Skip Kick. This move bears little resemblance to the original source but, IMO, Sonic the Fighters had a lot of lousy moves and this version is a great improvement.
Dsmash - Leg Throw. Yes, it's the move Dtilt used to be, relocated to somewhere more fitting. That said, I would like to see it a bit closer to the original source. Sonic does not do the splits. Sonic spins a full 360 about the supporting hand with his legs together. It would therefore be a little slower to hit behind him but, with most of the other moves improved, does it really matter that this one isn't?
Fsmash - Wind-up Punch. A whimsical move that, while comprised of entirely non-functional actions, is highly indicative of Sonic's character. It stays.
Usmash - Sonic Updraft. Such a good move and one of Sonic Battle's most iconic attacks IMO. It's quick and it hits up, little more to say.
Dair - Stomp. I thought this was Stomp already but it turns out it's a bad translation of his Sonic the Fighters move, Stomp Dive. It should be regular Stomp and, IMO atleast, it should work like Scott Pilgrim's.
Fair - Emerald Dive. Should have a tiny bit more forward motion but is otherwise fine as is.
Bair - Sonic Storm. The current Nair sucks in terms of originality so I'll be removing it, leaving a gaping hole in Sonic's moveset. You see, any good sonic moveset needs an aerial spin. To fill the void, I'm suggesting one from Sonic Battle. Sonic Storm has him go into a spin and propel himself up and backwards a bit, this momentum being offset by a wind based projectile. In smash, this projectile would be a forward and down pushing wind effect and, while it would travel a reasonable distance, it wouldn't make it more than about 1.2x the diagonal of a stagebuilder block. It would deal no damage, unlike Sonic's spin. The motion of sonic would slow after travelling up about 0.8x his height, at which point it would arc downward slightly until he returned to his normal falling trajectory at approximately the same height he started the move at. He would then transition into the same falling spin used in his Up B. The actual attack should be a bit less pathetic than that fall motion, however.
Nair - Windmill. From Sonic Battle, Sonic sticks one leg out at 90 degrees and spins horizontally. Should start quickly and allow for easy movement.
Uair - Splits. Yeah, I know I said Sonic didn't do these, so sue me. From Sonic Generations, sonic performs the splits, turning his upper body to face the camera as he does so. One hand points up, the other down. Both his hand/arms and legs/feet are hitboxes. In the end, it covers little range but is quick, both to start and to end, allowing plenty of movement during. Furthermore, it hits both above and below Sonic, making it rather useful in terms of protecting him from opponents not level with him. There is one rather abnormal trait to this move though. Inputting any direction but up (including neutral) and A during the move will cause a slightly different trick. Then another direction will perform another. The move is limited to one use per direction per time airborne, for a total of 5 in a row, with the combo ending once an input is missed. Since Up A counts as an input for the move, it cannot be activated a second time unless you land and retry.