Ikora has always said that. But in a lore perspective, the light gives us the ability to wield energies as a weapon. So think of the light as a gun and the different energies as ammo. Theoretically speaking, technically we risen can weaponize any source of energy, whether that be kenetic or maybe even gravitional energy. The possibilities are kinda endless.

You talk as if Ikora wondering about a forth possible element is leaked, new information. Shes been doing that since the game came out.