I think bile and mollys should both be 10, but I dont think bile is even that strong. Its only good if the tank is lit, but if he's not he can just run away. The only thing I dont like about it, is you get hit by it even if wasn't near you, so its pretty much impossible to dodge.
If this upgrade happens, I would like to see a scripted tank on every map, just to slow the survivors down so people can get heal points. Sometimes ill be at 1k hp as tank and close to heal, so i run away and try to throw rocks to get it, but if the survivors could see I'm low they would just push me and easily kill me before I get my heal.