How I Think New Dark Harvest Should Be Tweaked

What I Think The New Dark Harvest Should Be:

#Dark Harvest

Damaging a Champion below 45% health deal adaptive damage and harvests their soul, permanently increasing Dark Harvest's damage by 6 (1.5% bonus AD) (1% AP). Bonus AD and AP scaling can only stack 15 times.

Dark Harvest damage: 40-80 (based on level) (+6 damage per soul) (+0.20 bonus AD) (+0.15 AP) Cooldown: 40s (resets to 6s on takedown)

PBE Version for Comparison:

https://4.bp.blogspot.com/-X7nnMR2zXV8/W-X3XM01H0I/AAAAAAABK5I/nNMmgbfgl64OYuiokw67-voStPFZBO65QCLcBGAs/s1600/dark.png

Context:

Right now, the PBE version just kind of feels bad. Almost makes you wonder why you wouldn't just take Electrocute.

A way to fix this is to make it slightly harder to proc and make it less snowbally in teamfights. For compensation, it has a slightly higher uptime in lane and can scale with stats again (of course in a way that's not going to make it broken).