Pretty sure rengar is dead

An assassin that lets everyone know he's on his way to kill them. Something just isn't right with this logic.

This mechanic right here is everything anti assassin and it also defeats the purpose of even having a long range "camouflage" type stealth in the first place. It's almost physically impossible now to actually kill anyone because even a player in low elo with no grasp of map awareness would know to back off and regroup with allies. To add to this, his ult doesn't even give you ferocity stacks anymore. So with the stacks disappearing within mere seconds of not being in combat your ability to assassinate is dropped down even further.

Does rengar do more damage? Yes. Is his new ult horrible? Yes. Any other mechanic is fine, but if there's a global alert for when rengar is ulting then the ability might as well be changed to a invisibility class stealth with a 6 second duration. About the only time this ability has a use is when an easy to pick off player is too far away from anywhere to find safety (this won't happen in plat or above), or if the ability is instead used at close range as a leap.