We shouldn't just revert Rengar

There are plenty of people who look at Rengar and the idea of reverting him and say "if it happened to Kog'Maw, why not Rengar?". Well, frankly a full revert won't happen to Rengar because the reason he was reworked in the first place was due to his unhealthy nature that made it difficult for him to be in a comfortably balanced spot. Rengar was quite literally the definition of a feast/famine champion (Currently, that title is held by Garen). On the other hand Kog'Maw was changed simply for the sake of change, to try and make the marksman class more unique and give reason to pick one over the other aside from "who's best".

The reason why it was still fine to revert Kog'Maws rework is because the rework had game health issues tied to itemization and on-hit effects which ended up outweighing the problem of individuality from his previous version. As for Rengar, the current version holds more potential game health compared to the past iteration yet has strayed far away from his assassin identity. Currently, Rengar lies close to the bruiser class and is even recognized by Riot as such. There's arguments for which class Rengar should be a part of, Assassin due to the idea of chasing down a target and finally mauling their face in, or Bruiser due to the idea of brawling it out with your opponent and experiencing the true Thrill of the Hunt. Personally, I like the idea of Bruiser far more and believe Riot should continue down this road especially since it will give further distinction between Kha'Zix, who hunts for power and would not be afraid of playing dirty, and Rengar, who hunts for sheer ecstasy of claiming his targets.

However, I firmly believe Rengar in his current iteration is still unhealthy for the game in the similar feast/famine style as the old Rengar.

Old Rengar's issue was having far too powerful of scaling yet also being reliant on that scaling to have any use and, therefore, would have the potential to enter a feast state should he accumulate an excess amount of gold or would starve himself from scaling too slowly. The powerful scaling on Rengar was due to him being able to unload all abilities onto a single target without much warning all while getting a double or triple basic attack reset the latter basic attacks getting bonus damage on top of it, and this unloading occurred in less than a second in some cases.

Current Rengar's issue is relying far too heavy on the stacking mechanism of his passive. When maxed out he achieves 20% Bonus Attack damage and gets nothing from no stacks. This bonus attack speed as well as the guaranteed crit on his ultimate is what allows Rengar to still nearly one shot most people while having a bruiser style build.

My proposition is, rather than a full revert, meet halfway with what parts have been seen as healthy and perhaps some other changes.

1. Bring back the old Q, current one is clunky and seems to be overall disliked by most people.
2. Keep most of the current passive (amount of Ferocity needed + bonus MS when ferocity empowerment used) but revert the trophy bonuses so they are utility based rather than stat-based. Keep the method of gathering trophies so Rengar can't simply hunt the same target over and over.
3. Keep current empowered W cleanse and heal so Rengar has a way to get out of or maneuver through fights if played right.
4. Keep current stealth version of Rengar's ultimate (possibly remove the guaranteed crit?).

Adjust numbers accordingly so that he'll be in a decent state.

EDIT: MortenMBK1709 pointed out the old stacking mechanic feeling much better on Rengar and I agree due to the ability to gank pre-6.