1. What are Sonic's worst matchups? Why?
I think we almost all agree to Sheik, but I would also say Rosaluma, Olimar, just any match-up that does what Kinzer said. The reason why Sonic suffers against characters that zone him out or force him to approach is because...
2. What are Sonic's weaknesses?
... His approach options are ass. I disagree with Kinzer on range. I think Sonic's range is fairly decent, and even better than from Brawl overall.
Sonic's approaches are severely limited, especially from Brawl. We can't RAR Bair anymore because of the added lag, so it's unsafe. We can't Aerial Spin Charge Shield Cancel as it's been removed, so we lose that mix-up on approach. ASC is now far more of a commitment.
Spin Charges/Spin Dashes are overhyped. The best thing about them is people not knowing the difference between them. We have a lot of weird mix-ups with them which frustrate people, but the spin itself is really easy to punish if you know what we're going to do. If you shield and we spin jump, most character's can Bair OoS. If we hit your shield and don't jump, we're going to bank on the Lyric Roll (slow spin dash/charge roll) to land multiple hits as shield pressure and hope to cross-up. Even if we do cross-up, we go into screech stop which is punishable. If we do jump and plan on you punishing us OoS, we'll spring, which puts us in a bad spot if you just simply hold shield because...
Sonic's landing options are ass.
Lack of safe landing options and approaches are Sonic's biggest weaknesses that we work to cover up constantly. We have to be so much higher in the air for Dair to even autocancel anymore unlike in Brawl where it would cancel from Spring height.
Sonic being safe is usually an illusion, as people will see us use the Side-B hop invincibility frames to go through things so they think it's godlike but in reality the roll itself can be stopped with almost any jab, tilt, projectile, grab, etc.
Most people just complain about Sonic instead of taking the time to study how and why his Spin Dash/Charge work the way they do. Most people don't know the different utilities for them, so I could breakdown even more scenarios, or people can just read our stickies.
3. What can the other player do to punish side B (the only thing I could think of is Bair out of shield)?
I already sort of touched on this, but yeah, you're going to need to be more specific.
Sonic has all of the following options out of Side-B alone...
- Instant Spin Dash Jump
- Spin Dash Shield Cancel
- Spin Dash Hop into Spin Dash Roll
- Spin Dash Roll into Spin Dash Jump
- Spinshot
- Vertical Spin Dash Jump
- Vertical Spin Dash Jump 2
... Yeah.
4. In general, what should the other player do in order to beat Sonic?
Jab.
Dtilt.
I mean, just like any other character, study them? There's tons of frame data and breakdowns here, so it's not like we're keeping it a secret. We already sort of covered Sonic's weaknesses and options in most scenarios, so take that as a jumping point and do the research.