Why isn't there a way to see Bounty Hunter stacks for the mastery?
I mean, if you deemed it necessary for Rengar's passive to show what enemy's he has killed, then why not for the mastery as well? You can't say it wouldn't change your approach because it 100% would.. If Rengar wants to hunt targets for his bonetooth stacks to get more damage, then anyone who takes Bounty Hunter would have a similar mentality/approach if it was easier to keep tabs on your unqiue kills.