Georgeous photos! What a breath-taking place.
I even think the ones you label problems are very, very good. Then again, with a camera like the S2, I expect some tweaking will be needed. I've added a bit of levels to two of your; you can see them here:
http://www.flickr.com/photos/digicam/83034307/I'll make a few comments then hopefully some of the other mods will be around to give additional feedback. I've lived in Florida for more than 20 years so it's a long time since I've taken snow photos but I know all three mods have.

You have a lot of photos so I'm not able to look at all of them. Most of the "problem" photos were shot using centerweighted metering. Because of the vast range of light and colors in the scenes, I would have used matrix metering.
Of the photos I looked at, I didn't see one bit of blow out (white areas with no detail). In fact you have detail in every aspect of the "problem" photos I looked at. Honestly, that's great!
I thought I had counteracted that with the EV setting, but no.
The EV settings were probably fine, but to help control color casts, you need to adjust the white balance. Maybe use a custom one.
Also, I cannot seem to get the sharp focus to produce the beautiful contrast against peaks and sky that make winter so spectacular. The pix are almost always too soft and I have to use sharpening to bring them up.
It is probably due to the atmosphere. Probably a skylight or haze filter would have been better than a polarizing filter.
As to sharpening, I haven't met a digital photo that doesn't need some of it. A lot of "lowly" cameras such as the FinePix 1400 I used to own and which took some of the best images, have higher sharpening built-in. Most people using advanced digital cameras like to control things such as sharpening during post processing (editing). I keep sharpening off, but you may want to try increasing it. Same with contrast and saturation.
I don't think these muddy/color problems could be solved with a tripod.
You're correct.
I'm going to Argentina next month and am now thinking I should just rely on the point and shoot Sony as these pix are so disappointing
That's your call (bring both

). I have to be honest and say that if I came back with photos that I've viewed in your "problem" gallelry, I'd be thrilled. Then again, I am willing to take the time to sharpen, adjust brightness, contrast and color.