You're right. The flow of the branches pulls my eyes left to right. Maybe you can make another one in the lower right hand corner. A big one the covers the right lower side could look good or a small one that you would have to make with more rocks.
Wow. You are thinking exactly what I was thinking. I mean, to the word. I could have wrote your sentences. My debate was between making a the whole bottom right another, larger sand pool, or else just making one smaller one at the bottom right.