I think that is a cool concept, but would consider a couple of things.
1. Coral placement - it is generally easier to place corals on flat surfaces, which you have few of. consider the types of corals you would like and make sure there are good spots for them.
2. Height - If the Instant Ocean box in the background represent approximate tank height, I would consider lowering the arch a bit. It is generally advisable to build the scape no higher that 2/3 the tank height to allow room for coral placement and growth.
3. Surface area for bacterial colonies - You have a relatively open scape that looks great can be limiting on nitrifying bacteria. Either consider adding more rock, or use some form of media (Marinepure, Brightwel XPort bricks, etc.) in the sump to compensate.
I like the direction you are taking your scape. Keep it up and your tank will be beautiful!