So far, no one I've ever talked to has been able to figure out if there's something that affects the Mjollnir/Mjollnil side quest, so let's take a poll of what we got and discuss what we did, and see if we can figure out if there IS something or if it's just completely randomized.
Right now, off the top of my head, the only thing I can think of that I did differently between the first try (when I got Mjollnir) and the second (where I got Mjollnil) was that the first time I had Roswell and the second I had Rosary.
And there is no way it could be that simple, right?
It could be a matter of Milanor's morale or REP or something...