id like to see something make the boomer bile a more viable option.
i had a few ideas:

1. have it blind enemies like it does the player
i.e covering a witch with bile will make her temporarily wander and swing blindly rather than making a beeline for whoever pissed her off. they will temporarily not target the player but they can still be dangerous if you get caught in the crossfire

2. inspired by the deadrising wasp in a jar give it an aoe effect that blows off the heads of all common infected who get coated in it and a small radius near the biled infected. maybe for specials it could just hit them for the damage of a headshot. some specials it will insta kill others it will just hurt it and infected around it.

3. rather than an offensive item, make it heal survivors who are hit by it or maybe it could make infected not notice them. kinda like walking dead with the being covered in infected blood.

i dunno, these are just what i thought of.