I take it there are some special effects to the arrows of Light, but lets also remember that if special effects based on the world of Zelda is to be used, you need to take in consideration that in the world of Warcraft, Sargeras is invulnerable to all types of non-immortal attacks. Whatver Light is in the world of Zelda, it is generally not immortal in the world of Warcraft.
I bring this up, because in previous debates against Link, the element of Light from that world has been used to defeat virtually unbeatable characters with the simple argument "It consist of the Light", somewhat in the same sense as "Ganondorf can only be defeated by the Light"
Ganon's invulnerability is turned off for v.s. debates, like all characters, including Sargeras. The light arrows special power is basicly "Smite evil, +infinite d6 for teh lulz!"
Space being what it is, not very friendly to complex life forms, I'm seeing planetary destruction as a primary obstacle.