I need help toning down a character's power

[Notkastar]

I'm currently working on a balanced version of fist fighting marth I download a few day back and the Up B is the equivalent of a home run hit of luigi's Up B. I wanted to tone it down and give it the same power/ability of Roy's Up B while keeping the animation.

So my question is this: Is it possible to change a moves ability but not it's animation? and if so, how?