Not to wag my finger about it, but reusing characters just kind of feels cheap to me. Even if they happened to be "tweaked", it just cheapens the past experiences. Maybe I'd find an exception to ones that had died before they even started, or so early on that there wasn't any character development had to begin with. If a story is over, and a new story takes place in the same universe, also maybe? Like a D&D style campaign. But even in those circumstances I'd prefer creating newer characters. Just how I've always enjoyed roleplaying. By not limiting creative potential, where this concept is a fine example of it.