If Rengar Ult didn't detect stealth it would be a lot more fair
Rengar Ult atm not only stealths him, but gives him a 2000-4000 vision radius which reveals all enemy champions in the nearby area.
It also is true sight, so there is really little counterplay.
If it didn't have it, at least you could evade him that way or just have some POTENTIAL for counterplay. I mean as it is now he gets a huge movement speed boost, stealth, detection, AND he jumps onto your when he is in range. There is very very little counterplay to it and even if he isn't broken there should still be something you could do about it. I mean at least with TF ult you can have Banshee's to negate the vision but Rengar ult ignores it. :|