This would probably have been a good candidate for some HDR (see hdrsoft.com
for a good explanation fo the process if you are unaware of it). See my gallery for a shot of the same rock but looking the other way taken only a few weeks ago. Although I am still a beginner at photography, I have been been using PS and other editing programs for years (still not that advanced yet, but getting there).
I don't yet have a good eye for shots yet, but when I took this shot I did have a very good idea of what I would get at the other end of some basic processing. I guess this is my first step to becoming a better photographer in some ways. Many pro's talk about seeing and framing the shot beforehand, and those with some PS skills can also see the picture after some processing even before the shot has been taken. Maybe a little forethought could have produced a better result.
Play around with bracketing shots with bright and shadowed areas such as in this pic. You don't necessarily have to use it for HDR later on, but you could blend in the correctly exposed shadows into the pic with the correctly exposed highlights. Try underexposing in future, you can normally get back some detail from the shadows, but it's a lot harder to get back detail from the overexposed areas.
I think you did very well with the PS'ed version. I can see some ghosting around the people, but you did bring back a lot of the colour, although at the expense of darkening the shadows. I only played around with it for a few minutes and couldn't get much better, although I could only get a low quality jpeg from this site. More could be done with the original (preferably RAW) file.
Composition-wise, this is a hard subject to photograph. Both of our photos have a tiny bit of sky, the lip of the wave, the face of the wave. I see you cropped the tree out in the PS version. The trees in my version added to the composition I thought.
Whilst most of my long comment has been focused on the post processing and some wont actually help with this shot that is already taken, I hope that you will see that even if you are going to PS something, you still need to think about it before you take the shot. I see from your gallery that you have a good amount of experience, maybe just a change in thinking just before you shoot will help.
I hope nobody now actually thinks I know what I am doing, but I hope this helps you.