Judith might be a much more effective tool to paint Negan as a monster than just about anything else.
I might have agreed with that except would everyone's apathy toward Judith make us not feel as strongly toward Negan being a monster if he killed her? I feel it wouldn't work.
I think they would have to take Negan very differently if he killed Judith, but I like the idea. I think Rick could eventually reconcile in some way with other character deaths, but would be pretty impossible to let the guy that killed your baby daughter go on living.
I agree. No matter how apathetic you feel about Judith as a character - most people/viewers wouldn't take the killing of a baby very well at all.