Not really key position based, they're mostly things that match the letters like (i)nsert (a)fter (A)fter the whole line (d)elete (dd)elete a line (c)hange (C)hange rest of line.

Then the fancier ones like ct (c)hange(t)o which will remove the text from the cursor to the next character you hit. i.e. go to the open quote of a string, ct" replaces everything up to the end quote.

(c)hange(a)(w)ord will replace a word, (c)hange(a)(p)aragraph will replace a whole block... putting a number in front of the command will repeat it like 5dd to delete 5 lines.

I agree the muscle memory is a big thing but I use vim on both Dvorak and QWERTY (when I happen to be on site and not wanting to mess with changing keyboard layouts) and while I'm slower, it's just the ordinary slowness that comes with not using QWERTY very often these days. I think of the commands as being the letters, not their positions.

More to the point would be that if you're already an EMACS user maybe learning vim is not that important? Though it does tend to be more common to find some sort of vi on even minimal hardware than to find EMACS.

Strangely I use QWERTY on my phone and would find Dvorak odd for this purpose.

Edit: looks like ( c ) got turned into the copyright symbol thanks to some overeager parser