Without seeing its hard to tell, with Oscars and other large cichlids though, its best to have heavy decor that they cant move about too much, because if they can move it, they will. Any pics?
I would say for the size fish you have, then yes that centrepiece is taking up a lot of room, especially as full grown non of them can actually use it.
would look good with a really big heavy bit of bogwood as a centrepiece id also change the gravel for natural looking gravel . but thats just my personal preference.
looks better without the mass of rock but i think it needs a centrepiece still of some kind