The way I see it, Riot basically pulled a Skarner on Rengar. They came up with his kit around the idea that he'd only be able to jump to whoever he was closest to, so they gave him tools to support that - crit to reward getting a jump on a high priority target, CC cleansing to enable risky jumps to get someone that is being protected, long ult duration to have ample time to try and jump on who you want - but then after removing that due to feedback, just left him mostly as is, so he wounded up being the same fucking champion but with Zed levels of AD, a built in QSS and a 20 second TF ult.
Rengar's old ultimate was busted because it used to give him the location of everyone within a certain radius which let him bypass tanks and go straight to carries even if he didn't have vision. In addition, back then, Rengar was fully invisible when he ulted which meant that he could literally walk through teams unless someone was using a Sweeper or someone dropped a Pink Ward. Now, Rengar can only see the closest person to him when he ults, and he only gets the guaranteed crit if he jumps on that target.
Because Rengar is now part of the camouflage family, they kind of had to allow him to be able to jump on anyone he has vision on. On one hand, it gives him the ability to actually do something if a teamfight were to break out. On the other hand, enemies can see what he's doing if he gets too close.
Rengar's new ult is like 100x more fair than the old version. Like I said, the only thing that is/was broken about him is not the CC removal, but the additional CC prevention. Outside of that, idk how his rework can be considered Malzahar or Ryze levels of busted. Sure, he can still body someone super fast, but he's an assassin. It's kinda expected.
