One would think that the huge Dome is already illuminated enough:
The reason that the Dome of the Rock needs more lighting? Because the Arabs are upset that the rebuilt Hurva synagogue is more prominent at night time:
Hurva also is on a higher part of the Old City, which has caused much consternation among Muslims who are offended that the highest dome in Jerusalem is not Muslim.
Yes - Jews rebuilding a synagogue has offended the Muslim world so much because they interpreted it as a game of one-upsmanship that they must win.