I would point out that when using curly-brace languages, I never actually type either { or }. Instead, I use an editor macro that inserts the brace pair with appropriate indentation and leaves the cursor at an extra level of indentation in a new line between.
Other characters (',."<>) are clear wins on dvorak, and they contain considerably more semantic value than {} do in any language. ";" is also easier in dvorak.
Sensibly most English punctuation is on the left hand along with the vowels on dvorak; which is easy to remember.
Dvorak is very well considered. The combos: qu, th, wh, ph feel really nice.
What amazes me is the fact that the keys are staggered on a computer; I'd expect them to be radial; with my fingers. It appears no one's ready for a radical departure from the typewriter layout. Let's see what happens with the ipad.
Also, although those punctuation characters are indeed important (though I'd add '/', and '-' to your short-list), you probably type the alphabetic characters far more (just my guess, admittedly).