I think the biggest problem is there is no dark, anywhere. It looks like trees and a big picture window are reflected. In the real world this much light would blow away any other light source in the room so you wouldn't have soft shadows. The two fighters would be in silhouette because the brightest source is outside the room. The case lights are bright white. Every dojo or sports club Ive seen this kind of display in the bulbs were yellowish. Try changing the color a bit and turning down the intensity or even removing some of the lights. This will also increase the render times if you can remove some. If the weapons cant be seen you might try just upping the ambient component of the color. You sort of have two foci in this picture, the weapons and the fighters. If your intent is to focus on the case silhouette the fighters by removing the light from inside so that only an impression of the fighters remain.