It seems to me that in SSB for N64, Kirby was the guy to beat. Unless you hit him off the map, he was almost guaranteed to make it back because of how well he flew. He had 2 shields, the normal one and his Down-B, the rock. He had a powerful kick for a smash attack and his inhale was an instant-hit.
But, it seems the creators of SSBM realized how Pure Pwnage he was, and they decided to make some "changes", or, make him crappier. They threw in that hammer which sucked, and they brought the "Wall of Death" (The distance from the side end of the screen in which when crossed, would kill you) closer, so in turn Kirby's flight wasn't as effective. They also made him slower, and with Melee's new weight physic, they made him easier to knock out.
So, there's my rant. In closing I think Kirby just sucked really bad in Melee, but owned in the original. I saw his dreaded hammer in a screenshot for Brawl, but hopefully he's gonna get a revamping. Thoughts? All posts will be acknowledged!