First thing that comes to mind is detail... I can't see any detail in the roof which i'm sure is stunning to see in person. A greater dof woudl have helped maybe but in the current shot it looks u are trying to capture too much in one picture. When you are looking up at the ceiling at something like this... your eyes (at least in my experience) flow down the arch looking at small chunks at a time.
The 2nd part is cropping. A tighter cropping at the bottom to hide the half heads that are visible and possible waiting until the person taking the photo in front was done :)
Great perspective on the ceiling and lovely colours. I would like to have seen more of the ground to give the impression of hieght but still a good shot.
Love the colour of the arch. Could possibly have done with being cropped slightly from the bottom to lose the disembodied head and the person reaching up with their camera. Looks like an incredible building