The rework Rengar should have gotton.
Animation and gameplay should emphasize how ferocious Rengar is when hunting/killing prey
Passive: 5 ferocity, they don’t fall off. Rengar cannot use abilities while leaping, but the first ability he casts while in leap will immediately be cast upon landing. Rengar leaps on top of enemies. Landing on top of enemies slows them by 20% for 0.5 seconds.
Savagery: same as old Q, crits for 125% damage instead of scaling amount. Small lifesteal from monsters. EMPOWERED: crits for 140% damage and gains attack speed. The biggest reason old Rengar was broken because he could stack crit and, combined with the outrageous attack speed, would deal massive damage.
Battle Roar: Rengar ignores pain as he goes into a fighting frenzy. Rengar will take a % (based on level) of incoming damage and turn it into a bleed effect. Killing a target will remove the bleed, and the abilities effect. EMPOWER: heals for X – X amount, based on level, depending on how much damage he has taken in the past 4 seconds. Cuts down sustain, and keeps the clutch-mid-battle possibilities. No stupid CC cleanse.
Bola: Rengar throws the bola, however it will not fully deploy until in the air for a little while. If it strikes an enemy closer to Rengar, the damage and slow % will be reduced. Increase missle speed. Makes bola less of an issue during burst.
Thrill of the Hunt: Rengar stealths as is live, and generates ferocity until he has maximum, but notification only appears if he is close. When Rengar is in stealth he generates adrenaline. He generates 3/4/5 adrenaline per second, up to a maximum of 40/70/100 adrenaline. The more adrenaline he has, the louder his growls will become, and the more ferocious he will sound. His detection radius will also expand as he gains more adrenaline, as does his movespeed. Adrenaline quickly deteriorates after he is out of stealth for more than 1 second. When Rengar leaps onto an enemy, he will slow them by a % equal to how much adrenaline he has (100 adrenaline = 100% slow), and gains movement-speed % equal to rank + adrenaline level while heading towards his target for 5 seconds afterwards. If Rengar kills his target, the movement speed will last for the remainder of the duration no matter where he is facing.
TL;DR This emphasizes that Rengar is a ferocious hunter that stalks his prey, but doesn't just tell them he's coming outright. If Rengar wants to kill his target, he will have to be calculated, patient and smart. But once he finds an opening, they won't know what hit them. This shouldn't necessarily be THE rework for Rengar, but one that would feel like you're actually playing rengar, not just a glorified bruiser.