I do like the shot, there isn't much 'POP' to the shot. some of this is due to the weather as you've explained but I think a little PP would give it a little something. for me your watermarks have ruined it for me. I cant imagine the image would print out very well if someone saved it off here and also the water mark would be very easy to remove if someone wanted to so all it effectively does is ruin it for people wanting to look at the image.
I wouldn't know how to make this POP, I'm new to waterfalls, I last tried 4 years ago and I struggled then. Can you give me an example of a waterfall shot with POP?? You might be right about the watermarks.
There were a few more from this trip, I'd like to try on a different day, without rain!
I know they're not the best waterfall shots, a subject a need to get to grips with.