the second is my favorite, for composition reasons i guess. There is just more going on in that shot, my eye flows better through the entire frame.
As for improvement suggestions... i'm not sure that I would have done any better and I like the second one as is.
On the first -
1. maybe the horizon is too close to center, not enough "rule of thirds"?
2. the rock is nice in the fg, but it seems a little soft/blurry to me, maybe sharpen it up some, or use a smaller aperature?
3. All the action is the shot is the waves breaking, but it feels like we are so far away from the action in that shot, seems too small to really have an impact. I think I remember commenting on similar shots you posted in another thread, but those were right-in-your-face action shots where it made you gasp to look at them.
again though, nice shots, love the moodiness.
edit - I'm also wondering what effect a longer shutter speed (w/ tripod) would result in with these waves crashing around. Something to consider besides freezing the action...