Can someone please help Rengar??? Or make him stronger???

From my experience it feel like Rengar is a little be unhealthy. I mean i'm a Rengar main. On his early game he really weak. Every time you gank a lane he cant really anything. For example he can no longer E(Bola Strike) mid-air or do much damage with is q. On his mid-game he get stronger but lack a few things. A few major things he lack is that he cant really 1v1 much. For example if you where to 1v1 an enemy on the opposing team they can neither dash,leap/jump,flash,snarl, or even kite you till you drop dead. My second main problem with him is that he cant really burst down tank as much anymore. Even when i have and it still cant burst down tank. I even Zed can burst down tank really easily. In late game he really weak in team fight. He can easily get burst down within seconds. During late game his 1v1 still remains the same. He can easily die. He can did from tanks,adc, or even ap mages. I mean adc can stun or anything related and just 1-3 shot Rengar with crits. During teamfight when he jumps in the opposing team, the tank can easily stop him. But ever time the tanks stop me im force to run or else i gonna die from the rest of the team. At times the teamfights get harder for him. For example when you jump on the mid or adc champ the support,jungle, or top can force rengar to stop and run/die. My last reason why rengar should get stronger is that when he ult when people are not within his ulted circle people still get the ! on top of their head giving them a head up on what gonna happen and it really annoys me that I really wasted my ult for nothing.

P.S: Why is Kha'Zix the only hunter that got stronger but while Rengar got weaker. It just not fair for Rengar.

P.S.S: Thins is my personal believe. You dont have to agree or disagree with it. But i really do think that Rengar should get a bit more stronger.

If this is in the wrong board then my deepest apologies.