To be extremely honest, Sonic will never win a big tournament. By the way, this is under the current play of him, next week we might find out hes totally broken, and god tier, but who knows. Things are looking grim for our favorite 3rd party character at the moment.
Hes not something that can be played effectively against, well... just about anything. Yes, he is Sonic the Hedgehog, BUT, hes really isn't a character build for "competitive smash brothers". If you think about it, his final smash is obscene for a reason.
Every Sonic "main" here has a secondary that they play more because they don't win against good players with Sonic. I can't even consider myself a Sonic main anymore because my win ratios is almost zero as him. Beyond that fact that I am me, and you are you, no matter how you look at it, this is the case.
Sonic "pros" like LuCKy and Izzy aren't even really an acception. Yes, they do play Sonic far better than many ever will, but if you ask them they have a better "secondary" that they can fall back on at almost any point compared to their Sonic. They may even deny my statements, but they know its true. (if that makes sense)
It is HIGHLY doubtful the discovery we all have been waiting for will come, i.e., the new washdash, but I really don't think it is. Also, do not think this is a hate Sonic post, because it really is not at all. It is the truth. I am among the biggest Sonic fans, and I am a pure fanboy till the end, but my disappointments in the reality are beside me. It hurt me almost to a physical point.
You should also understand, or even realize, that Brawl is NOT meant for 1v1, no items, competitive matches. Regardless of other arguments, the truth is that Smash was meant for a party game that had a physics engine abused. The reason melee and 64 are what they are today because people like us wanted it to be a competitive fighter when that idea was not taken into consideration in is development. Sonic is an element of that game to promote brawl's calling card, the final smash.
Flame me all you like, but I have dealt with the actually of this, but still play a bottom tier character main in a game I play competitively when its not supposed to be. Why? I have no clue. I guess I can;t fully accept that my dream character is almost useless, but that is besides the point.
Sonic winning a tournament is a sign of the apocalypse. If anyone wins a major tournament with him, make sure you have access to a bible and do not stop praying to god that you will make it to salvation.
Edit: I misspelled "make" amek in the last part, and spell checking it comes up with "amen", and if thats not a sign or something then I don't know what to say. Also, I am really drunk, but my statements stand tall in the fight against them.