"mess" kinda hits the point. i dont even know what his identity is.. bruiser? assasin? walking zoning tool? 1v1 champ? aoe teamfighter? everything? nothing?
since riot mostly hit his base stats and utility i assume they want him to be an assasin (thank god). so imo the direction is right, but they need to shift some power around. after the rework rengar could do pretty much anything he wants because he had the tools and the base stats+scaling to do so, but now they removed some tools (ult zoning forever and cc immunity, which was needed) but even if he has a lot of tools left its quite hard to use them right when his numbers are low.
thats why he is weak for unexperienced players and still strong for experienced ones. an idea would be to lower his dps by hitting his cooldowns, but raise his scalings (rebalance numberwise afterwards). this way they emphasize his assasin identity and it'd be far less valuable to build bruiser. old rengar was actually closer to this, but the "either im fed and oneshot you in 0.2 seconds or i cant kill anything at all" wasnt healthy either.