About Dedede's CG, it's caused afaik by the inability to DI nontumble KB. Project M fixes that.
It's also ****ing ********, and this is coming from a Dedede main. I'd much rather have a good techchase than an option that invalidates entire characters, and general buffs to the rest of him. Like that zoning idea I pitched a while back.
I can name several MUs in Brawl that would be different without the CG. We wouldn't beat Ike for one. Ike jab > Dedede. DK would beat us, probably decently hard. Snake would be bad instead of even. Diddy would beat us even harder. Ganondorf, of all characters, would stand a good chance.
I'd rather have a good character than a character carried by a single move in tons of MUs.