Hi! I'm new here.
Part of what I like about Trek is the endless possibilities. Somebody died? So what? There's always an omnipotent being, alternate reality, B4 android template, or some other type of solution. I'm glad Janeway is back. I do like the evolution that some of the characters have been through in her absence-especially Seven and Chakotay. But to answer the OP's question, IF Janeway had had to sacrifice herself instead of Eden, I would have expected it. Especially with the short forward that Bayer wrote-something like "It's an alternate reality, just go with it." For some reason, that made it sound to me like Janeway's return would be temporary. I couldn't put the book down during the last 20% or so (Kindle-no page numbers!) because I wanted to know if Janeway would survive. I missed her energy and enthusiasm. I also miss Voyager reruns on TV.
Now I can't wait for the next book to see what happens!