Despite the fact that Rengar, LeBlanc and Camille have been dominating the League of Legends scene at both the professional and amateur levels, they survived Patch 7.2 without nerfs.
The trio has an 100 percent pick/ban rate throughout the LCK, NA LCS and EU LCS. In LPL, while Rengar and Camille sit at 100 percent as well, LeBlanc has a 92 percent pick/ban rate.
The three champions don’t sport outstanding solo queue win rates in Patch 7.1, which could be a reason they were overlooked. Camille has a 51.06 percent winrate, Rengar has a 49.75 percent winrate and LeBlanc has a 48.56 percent win rate, according to champion.gg.
Champion designer Andrei “Meddler” Van Roon did note on the message boards that Camille will likely see a nerf in patch 7.3.
We will probably be nerfing Camille in 7.3. Similar to your thoughts that'll probably include making her E only give AS if she hits an enemy champion. We're also exploring other nerfs to pair with that, with things like lower Passive shield strength, increased W and E mana costs and W becoming a decaying slow on the table (probably wouldn't do all of them, do want to test a range of things though).
There as been no talk yet of a LeBlanc or Rengar nerf, but you can expect them to eventually follow suit.