Well, I love number one, and infact I love number 2 as well. Usually, I pick out little things with images, and am quite honest if I don't like an image as well. So here goes
The problem in number one lies not in the B&W conversion, as I think this works quite well, but instead in the composition. It appears as though it has been cropped quite a lot? If so, I would keep the aspect ratio the same as it is, and expend the image to allow for the left hand side of the rock to be seen. Thus, by keeping the aspect ratio the same, you see slightly more water at the top and bottom, as well as the whole rock itself. This will help ease any possible frustration in not seeing the whole of the main subject matter, but also allow for more of that nice textured water to be visible.
The exposure however is good, and the highlights, though a little too apparent, work quite well also. Perhaps a levels tweak to bring out some contrast in the water itself? Here is what I mean... It's only subtle...
Number two is a really nice shot. I would however agree with shrimperblue that the whole shot would look better fully mono. selective colouring works well in more abstract shots imho as it lends itself to the genre. Compositionaly, I wouldn't change anything. Really good work on this one
Understand that I'm no expert, and I offer only my opinion. Some might totally dissagree with what im saying, but hey! That's life
hth