I think everyone agrees Melee is better than Brawl for competitive play. But that doesn't mean Melee is in every respect better, and Brawl is a huge step down. One big area that Brawl improved upon is items - the item game is much better in Brawl than Melee.
First off, it's easier to grab items. You can grab items with relative ease while dashing, while dash attacking, you can grab them out of the air, you can grab them while doing an air attack, you can grab them while air dodging, and you can grab them after your opponent has thrown them. This was all possible in Melee, but the timing is more forgiving in Brawl.
Offense is better for a couple reasons: first and foremost, the game speed. With everything being slower and floatier, it's to nail your opponent with a thrown item or a shot from a Ray Gun or a Super Scope. Additionally, being able to run around with those shooting items and the Fire Flower (as opposed to standing still when firing) gives you a lot more options. The last major thing is what happens when you throw an item and hit someone. Instead of dropping straight down, items in Brawl have a way of bouncing back in the direction of the thrower. This is egregious with the Trampoline, but it's noticeable with stick weapons, too. This allows you to keep up an item barrage longer, since you can quickly pick up the item you just nailed your opponent with and throw it again.
Defense is improved, too, which helps balance out the offensive boosts. Being able to grab items that your opponent has thrown more easily is huge. Multiple air dodges are a big improvement, too, since you can dodge a projectile without being a sitting duck for the next one coming at you. Also, the fact that you generally survive longer in Brawl keeps explosive items in particular from being too powerful. In Melee, if you touched an explosive capsule, it was curtains for you; those things could kill at very low percents (even at zero, depending on the stage - the top of Fourside was really bad in this regard.) In Brawl, an unfortunate run-in with an explosive isn't quite so lethal. Finally, the reduced hitstun means you have an easier time escaping from Super Scopes, Ray Guns, Fans, and the like. In Melee, if someone started firing a Super Scope, you were basically trapped until it ran out of ammo. Not so in Brawl.
The two items removed from Melee - the Red Shell and the Flipper - were, in my opinion, the worst ones, so it's no loss. The Bumper is far more effective than the Flipper because it's knockback is so much better, especially on the initial throw. The Red Shell was just as bad for you as it was for your opponent; all it ultimately did was wipe out one of the platforms for a time.
The only thing Melee has relevant to the item game that Brawl doesn't is power shielding - the loss of which is mitigated by the Franklin Badge and the easier time grabbing an already-thrown item.
tl;dr: it isn't fair to totally denigrate Brawl at the expense of Melee. They're different games with their own strengths and weaknesses. Some of the changes that weakened Brawl's competitive potential strengthened other types of play - item play, for one.
