Instead of “when hit by melee attacks”, because it makes it pretty annoying and unreliable when you’re facing a caster at close range and the proc won’t trigger, since you’re not getting hit by melee attack, effectively taking a good portion of the efficiency of this T3 proc which is already underwhelming, considering the requirement to unlock it.
Also increase the activation chance to 25%, so that it procs a bit more frequently as well. Maybe raise the cooldown a bit to compensate.
Oh, and the knockdown is very unreliable and annoying for a melee build, so replacing it with a fumble effect with a 1 sec or so duration would make it much better, since almost everything in this game is immune to being knocked down, for whatever reason, plus Fumble would make more sense, since you’re blinding everybody with the “divine light of empyrion”.