G&W really isn't that bad. But it's whatever anyway because he's receiving very beneficial tweaks to him for 2.5.
Well to be fair, you compare G&W with other characters and there aren't many he is better than. Compare him to the Melee tier list for example. People near the bottom got some solid buffs, and a lot of characters near him in Melee also aren't in yet. No Pichu Roy M2 Kirby Yoshi.
Other characters around that area got noticeable buffs. Bowser Zelda Link stand out the most, DK Luigi got some things, then obv Mario and even Pika got the QAC stuff.
You look at Brawl characters that are added, and again most of them are clearly better. The only questionable 3 I think would be Charizard Wario and Ness. Wario could literally fart his way to a spot better than G&W if he had to.
In the grand scheme of things, compared to solid Melee characters, compared to the buffs that other people have gotten, he's not really doing that good. It's very likely that Ivy and Squirtle will be better than him too. He's an obvious candidate for bottom 5 as the game is right now. Whether he's an average character going against amazing characters, or a struggling character to begin with, he looks and is quite bad compared to everyone else. There are a few changes I personally would do to break him free of that spot, one important one being give him the old Dthrow back/give him the old Uthrow Dthrow throw game he had. Another one possibly buffing his horizontal drift after using Upb or letting him angle it to the side a bit more. Making Nair a bit bigger, just small stuff. I am looking forward to whatever he gets in 2.5, I honestly hope one of them is the old Dthrow. It feels much better than the current one, gave him more mixups and combo options on the cast in general, etc