I don't see a problem with the decor.... to each his own. The simplistic look is great. Open and looks like it gives a nice flow to their swimming patterns in that large of a tank. If I were to give any criticism at all, it would be the rocks stacked in the middle do look a bit 'placed' - not as would see naturally, but I'm a freak on making my tanks look natural.
Makes me miss both my Morrii Muzi, and my 240g long...
I don't even want to know what the price tag on that many tropheus would be, though that is a 400 gallon tank so I'm not thinking that was a concern.
What gen are the fish and how long have you had them? Any breeding? Ha, I just imagined what it would be like to try and catch a female to strip in a tank that size, going to let them spit in the tank?