Good points on both sides, but there doesn't really need to be two sides here. I shot my last wedding in RAW, I shot my last football game in JPEG medium, and my last candid job in JPEG large. I shoot according to the job, but 90% of my jobs, to include studio work, are JPEG jobs.
Print size is a consideration, but color does not enter into it. The vast majority of labs require images to be in sRGB, this means no fancy "extra" colors, so RAW need not apply, but, for total output clarity on a 20x24 print, a RAW will most likely win over the JPEG, even if it is by a small margin.
Saving a shot because it was improperly exposed is a great excuse to not learn proper exposure. I have learned to ignore my in-camera meter and to NEVER trust aperture or shutter priority, I will use these on occasion, but I do not place all of my faith in them. My hand held meter and knowledge of WHAT to meter and WHEN to meter now play the dominant role in my exposure decision. (for example, metering for the grass minus 1/3 stop after the sun has set for a night football game, perfect exposure every time, just watch for the "dead zones")
I am not accusing anyone of not knowing how to meter, I just think that the "fix it later" attitude leads to piss poor photography. If I cannot show my client the image as soon as I take it, with confidence, then I have failed as a professional.
As for white balance, this is another fall back that can be corrected before you shoot, and even after with JPEGs with the correct software. Grey cards do work, I use them daily. Not only grey cards, but I had my lab print a card (8x8in) with white, black, red, green and blue on it, and then mount it on gator. This is my reference card for most jobs, I shoot the card with the grey in the middle for custom white balance, and keep the image in case I need to reference it for later color adjustments in PP. When traveling light, I keep a pop-open grey card that I just shoot on site and make my custom WB.
Power Retouche
has an awesome WB correction tool that works great on JPEGs when you forget to do a custom WB (oops...) or if you simply don't have time because shooting conditions change too quickly.
As for PP time, batch is just one more step that can be eliminated. Time is always against the shooter, every step that can be removed from the PP is time saved, and this means that the editor, or the lab gets the images faster. Check out this
quick site I threw together for a charity event at a local school. I shot all JPEG, and I put in about 30 minutes of PP to toss the OOF, and non-story telling images. I cropped a few and generated the web page. The site was up the next day, and the client was thrilled, time is everything.
RAW has it's place, as I stated, I shot my last wedding in RAW, knowing that the bride wanted "over the top" artsy images, you know, the over-processed kind that are so gaudy that they almost hurt the eyes to look at....yeah, that's what she wanted. Well, I work for money, not principle, so I did as she wanted, and shooting RAW gave me the ability to jack around with exposure, levels, and saturation in a way that I could not with JPEG, so RAW made sense.
I feel that this will always be a debate, and there is no correct over-all answer, but, in most situations, JPEG serves it's purpose very well, and those of us who shoot it everyday and create salable images from them are proof.