I don't think the HDR is over-done. The first thing I notice is that the horizon is not level. I think I would like to see more of the cherry blossoms and less of the dead space in the water and sky. Just my opinion.
I'm certainly no expert, but the main center of attention of your picture, are the rocks on the ground. My eyes are immediately drawn to that. I can partially see a beautiful cherry blossom tree ( and is that a weeping willow also? ) to the right and a nice bridge and cityscape in the background. All of which would have made much better subjects.
I do not think the HDR is overdone. On the contrary, I think its as it should be -at least in my eyes- : you do not notice it.
But I agree on the faults in the composition. I see you created on the right side below a green triangle. Triangles are always unbalanced, especially if you do not balance them with some 'counterweight' in the photo.
I think the photo would have been right, if you had taken a step forward and dropped on your knees. In that case the disturbing grass would have been gone and if you had pointed the camera a bit more to the right and so would have gotten more of the tree, it would be better.
But please remember: composition is difficult because everyone has his own opinion on it. I'm pretty sure there are members here who have more experience as I that do not agree with my comments:smile:!