Oversight most likely.
01/01/08:
"HEY SAKURAI! All these moves have momentum breaking properties and will allow people to live forever recovering"
"Hmm, best change that, make them all send them straight up so they die at their stupidity"
"Okay, Sakurai, you're so smart and sexy and I wish you'd reconsider making Marth's dtilt longer than MK's, Marth will be broken otherwise"
"Yes, you're right, we don't want Marth to be broken, and as MK is so weak he needs the longer range, also we should make the move trip like 99% of the time too"
"Great thinking Sakurai-sama!"
05/01/08:
"Hmm, developer-san, I just realised game and watch kinda sucks, let's double the range of all his moves, recode the priority system for just his moves to be above everyone elses, and also double all the killing power of his moves too. To make him balanced. Also don't forget to make it so he has no lag after any of his moves, only fair"
"GOOD IDEA SAKURAI-SAMA! This game will be the most balanced ever"
*developer-san recodes G&W, oversight of bucket*
02/02/08:
"Sakurai-tan! We accidently made G&W too broken!"
"Who cares, the preorders have already made us hundreds of millions of American dollars, and with the American money market being so God Tier, there's nothing to LOSE!"