Testing this character a bit, I notice that his movement is really nice, but his aerials don’t exactly complement his movement, with the biggest offender being Back Air. There’s nothing wrong with it being a slow move, but it doesn’t exactly set up into anything and doesn’t kill. (I say this because the animation implies that it would be a kill move.) Other than that, I feel side B is an unsafe move that’s useless in every situation. Recovery, approaching, comboing, and punishing. I feel it would be better for side B to be replaced by a projectile, maybe Sonic Wind from Sonic Battle, which I’d assume work similar to Terry Bogard’s “Power Wave” in SSBU. Your version of Sonic is the best in the workshop to me, and I feel making those two small changes would make him a more competitively viable character. As of now, he feels very underpowered, especially compared to the other Sonic mods in Workshop.

Thanks for the feedback ^^

-Regarding his aerials, Up air is the way it is primarily due to a lack of sprites for the type of move I wanted. Although now I have an idea of what sprites I can use to make the move closer to my original vision, which should also help it as a whole. Not sure what issues would arise from the other aerials (aside from Bair), though, as in practice I'm able to string together combos into D-Air and F-Air easily. With a bit of momentum you can also shorthop cancel dash attack and get two N-Air hits leading into whatever else you do afterward. Maybe I should put together a gameplay video showing what all he is capable of ... Anyway I could try tweaking the knockback and angles of the aerials if that could help?
-Regarding Back Air, I'll see what I can do. I may end up increasing the knockback scaling to help it kill faster.
-I don't want to give a projectile to Sonic because 1. It doesn't really fit the character in my opinion, primarily seeing as Sonic is meant to be a fast fighter with very poor range, and 2. With the easy combos from the Dropdash I feel like giving him a projectile might make him OP (and I'm already working on another hedgie, hint hint, so I don't want to be too repetitive). I'll see what I can do about Side B though, I agree that it is rather underwhelming at the moment. Something of note though is that Side B can destroy projectiles like Zetturburn's fire shot, so maybe I can work off of that and make it a defensive approach move? Perhaps adding some soft armor might help?

One thing I would like to emphasize is that Sonic's combo game relies heavily on his spin attack, which is how he gets the most damage and what best leads into his aerials. That said, I will do what I can to make it so that he doesn't rely on his spin attack as much as he does right now.