User blog comment:Rossendale2/Balthasar, The Wall of Demacia/@comment-6399518-20130929105836

not to be negative but broken passive is broken with a capital F. first blood usually gets the killer 300 gp, and 50% of that is split amongst assists. unless you're on Aram that'll be 300 gold to both killer and the assist with that passive. 600 gp to your team. just for first blood you'll end up getting gold comparable to some of the mid game objectives through one champ's passive. and in teamfights this champs level would skyrocket.

if you really want this as a passive you may want to drop it to something less potent, such as 5-10%. that way you get maybe 1-2 gold per minion, 15-30 for first blood (not including the 50% gold you'd get from the assist), 7-15 from turrets. and the xp would not be much different from zileans passive, except its only on you to make up for the gold advantage.