Hi there,
Sounds like we use the same prcedure for similar reasons.
Yes and no to your question, and sadly, a bigger NO that there isn't a true workflow. We're into the best workaround FOR YOU. Mine is FOR ME, and (as my wife will tell you, I'm unique .... which I take as a compliment, errrrr).
Yes, the time to batch export and then import may be faster, technically, possibly, maybe, who knows?
No, the issue of getting the photos tagged back into the stacks (if this is of use to you) becomes manual activity and is unsupported by the system outside of sort conditions.
You can easily overwhelm memory with CS2 loading images and Aperture there as well, so I tend to do 10 or a dozen at a time ... more if image size and memory permits. Run an Action in CS2 unless masks are needed, Save and Close. On Save, the image is placed back into Aperture without any further work on your (i.e. MINE since I am LAAAZY).
BTW, somebody else mentioned this. I am a big fan, but have ghad to learn to work with quarter tone Levels. If the color shift is most needful on the skin tones, and less objectionable elsewhere, you may be able to use the quarter tone adjusts in combination with exposure and white balance adjustments within Aperture. Oh, how I would like selection and masks!!!!