Nice Kerioak! See how that gives purpose to the posture?
As far as being totally happy with an image, I wish for us all to experience that from time to time. However that little grudge we hold to an image, that undefined itch, is the kind of thing that drives us to improve! It is for each artist to decide when to abandon an image and put new ideas and observations into a new image or keep working with an image to improve it. I would note that if you want the fun of seeing your own path of improvement made visible, it can be a good choice to set an image you are not quite happy with on the finished pile. They become signposts on the path of your artistic journey, showing where you've been and how far you've come. :-)
I will offer a thought about the driftwood. This might be a place to try your hand at foreshortening on that log. As depicted, it appears almost to run in paralell to the horse's path and for my eyes it seems closer to the ocean than the horse for much of it's length. I would propose sticking one end of the log in the ocean and have the other end come right off the bottom edge of the painting. NOTE: I am happy and willing to draw some lines to stimulate your understanding and help imagine the things I'm talking about. I ONLY do that with permission however. Let me know. :-)
Only you can decide if you feel like continuing or moving on. Either way this is the kind of work that get's you further toward understanding. You have a good many solid things going on here. I really love that you cared enough to put in the pebbles. :-)
One account,
many possibilities