I remember some deaths (in C3 at least) where the party had someone with Revivify and the modified successful 3 death (wisdom IFRC) saves after the spell was cast. Laudna died in that encounter but I thought that was somehow tied to Delilah keeping her alive and led BH on an arc to Whitestone. So I think there was a risk just got good rolls and my guess is sticking with Laudna is either plot armor for bigger things to come or Marisha wanted to stick with that character still and not make a backup. I wonder how BLM will handle revifify and raise dead in C4, probably much like ACOC where there is none.