User blog comment:TheGrouch91/My idea how to fix Rengar/@comment-74.67.111.208-20130329022703

None of this will "fix" him. All you've suggested here are some very minor numerical changes. Rengar's issues stem from his resource system, since it forces the abilities to be weaker 80% of the time, and slightly more powerful the 20% when you've empowered them. Additionally, it forces all abilities to be balanced so that they're not mind-numbingly broken when double cast, which again forces his un-empowered abilties to be so unimpressive. On top this, his passive and lack of mana encourages him to mindlessly spam to reach an effective level, instead of encouraging players to stategically pick their abilities. Since he doesn't have to manage a resource outside of deciding what ability to empower, Rengar is free to continually spam whenever the abilities are off cooldown - a factor that must be balanced for, and again, forces the overall strength of his abilities down.

tl;dr: Rengar's abilities are not the problem, its Ferocity and its mechanics.