Glass Cannon Rengar
Is this still pretty viable is my main point I want to address. You can no longer do a triple Q due to nerfing, so if it is, what do you suggest as a build?
I'm thinking along the lines of something like this:
,
,
,
(due to its active maybe?), and maybe a
. And then boots of your choice. Not too interested in the runes or masteries as much as what items you suggest. Maybe instead of BotRK, get a Youmuu's Ghostblade?

Other builds are good but I think this is probably more cheaper than the others. You could go hydra but you don't really need the life steal since you have sustain. All you need is tiamat, Last whisper, ghost blade, and boots of mobility if you want want to 2 shot some one mid game. Triforce IMO sucks on Rengar, you don't get that much burst compared to Infinity edge. The thing about this build is that you can duel with tanks due to the amount of armor pen.