Jumping onto the bandwagon making tier lists. >< Btw, order within tiers is indeed from left to right.
S- Metaknight, Snake, G&W
A- Marth, Toon Link, DDD, ICs, Pikachu, R.O.B.
B- Zelda, Sheik, Fox, Wario, Pit, Kirby, Lucario, Squirtle
C- Charizard, Luigi, Mario, Bowser, Ness, Lucas, Wolf, Olimar
D- Link, Ike, Peach, Samus, Yoshi, Jigglypuff
E- Ganondorf, Ivysaur, Captain Falcon, Sonic
Possibly unusual highlights:
Metaknight does lose to Snake, but is better overall in terms of his matchups against other characters. This is because he's safe on block, can move and approach fast enough to pressure campers, and actually has better kill options than Snake with his Up-B and D-smash, which don't get diminished since he has too many attacks to spam to get around diminishing returns. On top of that he's arguably one of the best ledgeguarders in Brawl, and he doesn't get gimped, which IMO is more important than being heavy.
I put G&W up in the S tier because U-air stalling is surprisingly broken in terms of what options it can limit your opponent to. If you do it right, they cannot punish it and it can only be escaped by air dodging or DIing off of the stage. The only characters that can reliably outspeed G&W with DI to escape stalling are clearly worse than G&W, such as Yoshi, Jigglypuff, and Wario. G&W also does several matchups better than persay Snake. Snake has a lot more trouble dealing with characters like Pikachu, Zelda, DDD, and Falco, and most campers in general. G&W however clearly has very good matchups against those characters. Also btw G&W is undeniably the most powerful character in team Brawls when paired up with someone like Zelda, which I believe deserves to be recognized.
I put Wolf lower than I think most people put him. This is because his recovery is horrible, much the same way Ganondorf has horrible recovery since he can't always make it back to the stage, and this also makes it harder for him to ledgeguard. His projectile spam as far as I'm concerned isn't all that good. Rather slow and short ranged.
I put Luigi, Mario, and Bowser in the same tier. Luigi honestly isn't all that much better than Mario since he deals with camping worse and his ledgeguarding is very bad, while Mario's is very very good. Mario is also the best camper of the three by a longshot. Bowser isn't better than Mario since he gets comboed much too easily and gets outcamped badly, but he does better than Mario in some matchups where camping is less of an issue.
Captain Falcon is horrible, but Sonic as far as I've seen now really seems worse. We discovered that you can still D-air to Knee if you autocancel the D-air, and Falcon has other attacks which kill better than Sonic's attacks since they have more knockback like F-smash, D-smash, and U-air, and maybe B-air. Sonic overall has less range than Falcon and Falcon seems to approach better due to having one decent priority attack the Falcon Kick to help that.