I like the islands look because I really like the natural sea floor look to an aquascape, rather than just a big pile/wall of rock. I'm also not a fan of unusually stacked rock with holes and caves under every single rock, where it looks like it might topple over at any second (even if its connected securely) because you just never see that kind of rock formation in real life in the ocean.
If I had your tank, I'd probably make a 2 or 3 island setup. one bigger tall island, and one smaller one, with a nice little clearing in the middle for some cool LPS or a clam. Or I might try a 3 island setup with 2 large islands opposing each other, and a smaller island right in the middle to make it interesting.
make your islands in the tank now, but next time, set them up, and build them together with epoxy outside of the tank before you put them in there. you can get much more interesting shapes when you can build it on your kitchen table, and epoxy them however you want.