Yeah finally fixed Kat being listed twice (the lower listing was her old self).
Rengar, I'm not really sure why he didn't catch on faster. I ran his numbers on release and simply said "Wow, in optimal situations this is broken, and an organized team can easily create these situations." That said, the difference between a good and a bad Rengar is not their ability to fight, but rather their build and when/where/how to engage. TT caught onto his strengths as fast as I did, and I'm seeing Rengar bans in SR ranked now so his time as a power is definitely limited.
As for Abyssal, it is a situational item. Given speed shrines and the nature of teamfights on Dominion, the aura may not always apply when damage comes in and the flat pen might not be utilized much by allies. A case could also be made for an enemy seeing the aura as a giveaway for who might be in fog/brush, but people noticing it on their status bar is rare. Overall, in most situations it is better to grab a Void.
Jax will actually beat Ryze in bot lane very badly until late game. I recommend Nunu, Jayce, Urgot, Diana, and Malzahar for dealing with him. Yorick and Kayle will also sometimes win. Tanks with minion clearing like Maokai and Udyr can also indefinitely stalemate a Jax.