Re: The Jaimie Alexander/Lady Sif thread
I think there's still a great chance of Thor/Sif happening. It's obviously not gonna happen in Thor 3, but in future Thor movies. I think Marvel has too much invested in this shared universe to just reboot it in the near future. They'll continue it for quite a long time. I do think actors and whatnot will definitely be replaced, but I'm sure the continuity will be the same for many films and years to come.
The first two movies have already established heavily that Sif is into Thor, so when it comes time to explore them, it won't have come out of nowhere. Once the Jane/Thor romance has run its course, they'll be free to explore it more fully, just as they did in the comics. I just believe it's happening one way or the other. This is essentially a Gwen/Mary Jane situation. Once they get Jane out the way after a couple films, in will come Sif. I think the current rebooted Amazing Spiderman series is going to do the same thing as well. People just have to be patient.