I don’t think Mercer lead will be good for him. Still get resist on doc and a command and turn two kill him. But really fighting Mercer is lucky. I would go almost glass cannon behind Mercer on defense just cause u want to do some damage first round. Would not waste a space for a shield is what I am saying. But that is my opinion.
Now if they included a negan or wayland you could not kill turn one yes that would be bad but that doesn’t have to be behind a Mercer.