Alright, this is all good stuff. I also had a discussion about fast hands with Kwan yesterday and learned some very interesting things about how the human brain works. I'll have to see if I can find a definitive article to point people at, but I'll try to share what I learned because I think it can be one of the single best pieces of advice you can give someone trying to improve their tech skill ( I'll also see if I can get him to chip in on this later).
So first a quick disclaimer before diving into this: Muscle Memory is a kind of a misnomer. The signal/information used to trigger specific chains of muscle responses does not reside in the muscle. For more on this read through:
http://en.wikipedia.org/wiki/Muscle_memory ( Note this article also talks a lot about what I am going to talk about ).
Would a guitarist with years of experience coming into Guitar Hero be any better than a novice guitarist? I mean he should be right? He has fast fingers and can read through sheet music at a good speed, so since he has the two skills nailed down he should be golden right? Wrong.
The guitarist won't be any faster than the novice, because the guitarists "Muscle Memory" relies on shifting his fingers through different cords, not pressing down 5 buttons in a vertical line. Most dextrous tasks actually have nothing to do with building your hands muscles, but practicing the motions again and again. To extrapolate on this, you will not get faster at smash or faster at being a guitarists from being fast at the other ( Yeah I know, there goes my dreams of rock stardom too ).
"Muscle Memory" is actually the packaging together of simple motor actions to be executed in ordered succession without conscious effort. Once you have mastered the wave dash you don't think tap-Y lightly, hold control stick in a direction and slightly down then press l button. You think I want to wave dash left or right and then your brain sends that packaged command to your hands, which then execute them. This is why stroke victims often need to relearn basic motor skills, that set of commands you learn as a baby to walk and pick up things becomes fuzzy ( more science regarding what happens to memories when your brain is damaged, not going to get into it now ), and you have to recommit it to memory. You can also overwrite old "Muscle Memory" with new ones, like when relearning your key binds in an MMO after you redo them. Learning claw could count for this if you stopped using normal control style all together ( which good luck with that not that it would impede you learning the claw ).
The cool part of all of this? The more you do this the better you get at molding your "Muscle Memory". If you feel like you pick up characters or new tricks faster now then you did at the beginning of your smash career, it's because of this. I am blanking on the name, but there is a comic book artist who suffered a stroke midway through his career and had to relearn how to draw, but he was able to come back from the basics much faster because of this.
Here is the TLDR: The only way to get better at tech skill is to practice, and not just practice the skill, but practice doing it perfectly. Drill yourself on how to do it again and again. If you want to get faster at learning new tech, learn more tech and you will get better at learning it.
Basically, what Scar said is correct, just practice with whatever control is comfortable for you and you will eventually reach the speed you want. Mind you experimenting and finding a control style you like will also help you simply because you will be more comfortable with it.
If you are interested in the topic there is a book out called The Brain That Changes Itself:
http://www.normandoidge.com/normandoidge/MAIN.html with more on this subject.