In the spirit of being helpful, not judgey and mean.....As is, when I look at it I see three rock piles in a row. I see a nice cave to the right side, but not too much other than a pile in the center and left. All 3 piles sort of look like they run near the back wall, but maybe more or less in a straight line.
What about moving the middle pile towards the front of the tank, which gets rid of the 3 in a row look. If you have any long flat pieces maybe you could make a bridge to the middle pile from the left side? Something like that. Maybe add in a little more height to one of the side piles, to get rid of the 2 larger piles looking essentially the same.
Here is a picture I like to keep in mind that illustrates the rule of 1/3's and composition. I think it helps me visualize the layout a little better.
Just ideas, I am by no means an expert. I like the overall look of the tank, how long is it? Looks like a 7 or 8 footer in the pics!