Graves' passive is needlessly easy to drop

I mean absurdly easy. It should have a timer and resets like draven's axes, so you can keep it up between waves, instead you risk dropping it in between last hits.

It's also not really very interactive. It's from a time where passives were passive, and should be based on damage dealt/taken by source and abilities used, rather than by time spent in combat.

Proposed Change: Graves' passive takes 6 seconds to drop, instead of 3 (draven's axes take 8, as you get a refresh when it's thrown and then when you catch it 2 seconds later, plus Q resets), and stacks are given when he deals or takes damage. It can be refreshed (not increased) by using abilities. No numbers changes needed. I like the 30 late/10 early. Feels significant and you notice it during trades, it just needs to last longer.