Hmm...
Is that critique based off the videos from over the weekend?
I have to disagree with a lot of that. I'm not a Sonic main, but I know you as a player.
Several things he mentions that I've never noticed you having a problem with:
1. Recovery: I've never seen anyone gimp you—ever—what's so bad with your recovery? Since Sonic has a hard time sweet-spotting the ledge, nine times out of ten you recover high and when your opponent gives chase you d-air. The outcome of this situation is usually (a) you hitting them on your way down as they rise, (b) them airdodging through it and being unable to punish you upon landing due to the speed of the move, or (c) them baiting the attack and attempting to punishing you during the move's ending lag, which is extremely difficult because no fast-fall outspeeds Sonic's d-air, meaning you reach the ground before they do. The only characters I've every seen harrass your recovery are those with multiple jumps (D3, Kirby, MK, etc.), because this allows them to reach you at the height of your spring where you're the slowest/have the least aerial mobility.
2. F-smash: How many kills have you gotten with that move? I know it has major start-up lag, and its easily punished, but you generally only use it when the opponent's already used their second jump and you've predicted where their fall is going to lead them—then you use Sonic's speed to get there and you hit them with it as the come out of their airdodge. Other than that set-up, I don't really recall you spamming it or anything, so I can't see how that's a flaw in your gameplay.
3. Edge-game: Again, I just don't see this. You're forever chasing me off-stage with those back airs, low & high. Primarily high, though, you generally go for the 'semi'-spike when someone's recovering below the stage, and then you follow that up with a quick spring to get back to the stage. What else can Sonic do as far as gimping goes? I know the homing attack works on occassion, but it's easy to see and gives plenty of time to react, which, in my mind, results in a wasted attempt that could have been something else. I guess it's one of those mindgame elements of Sonic.
Honestly, if I were to critique you, the only things I would agree with this guy on are:
1. Follow-ups after a blocked spin-combo—stop u-airing!
2. Possibly varying your low-percent approaches. I don't know what Sonic has as far as 'true' combos go, but if they're there, use them.
Those are just observations I've made since we've started playing together. The only thing I could offer to you as a player is using safe moves, and I know you're going to say, "Sonic doesn't have safe moves! No priority, no range = not safe!" However, they don't always have to be 'frame' safe, but just unpredictable.
EX:
jab -> jab cancel -> grab
out of the grab? anything really, and long as you bait the airdodge. BRAWL'S SUCH A MINDGAME!
dtilt -> dash away -> dash attack through opponent
I could be wrong here, but Sonic's dash attack sends you through and behind them, right? Good mix-up when combined with other things.
As a Sonic main, I can't critique you, but as a player, I think you're pretty solid. Once you grasp just how untechnical Brawl is, rather how much of a thinking game it is, I think you'll progress in leaps and bounds.
As I've argued time and time again, it's all about set-ups, brickwalls and traps. In order to win, you have to put your opponent in a position where you can limit their options. This allows you to narrow your next actions down, based on what they have available to them—then you simply respond with the safest thing you have at hand. You won't always get it right, but at the least this will reset the situation to neutral, allowing you to try again.
If you don't know what I'm talking about, key situations for this are when they're on the ledge, they've missed a tech, or they're out of jumps. When your opponent's in one of the above, no matter what character you play, you should ALWAYS be able to get off more damage.
Then comes the next part, which is keeping it unpredictable, because a smart oppoenent will recognize the same set-up once they've seen it used. Now's when you have to be creative, mix it up, try something new, keep them on their toes.
That's Brawl, that's it, learn to do that and you'll have the best Sonic evar.