It looks like Marvel is replacing Thor with a new Thor (which seems weird cause Thor is his name not a title but whatever) in the comics who will be a woman. Announced on The View of all places, details and her real identity are still sparse and we only have the one picture so far. According to the announcement
"It's a huge day in the Marvel Universe. Thor, the God of Thunder, he messed up, and he's no longer worthy to hold that damn hammer of his. For the first time in history, that hammer is being held by a woman. That's right. Thor is a woman!"
I am sure this change is permanent and won't be changed in a few months/in time for the next Thor blockbuster. Comics wouldn't do that.
Of course she isn't the first woman to prove herself worthy to wield Mjolnir. Storm, Rogue and Black Widow have proven themselves at one point or other in various continuities. Even Wonder Woman in what looks like was probably a ridiculous cross over.
I am pretty good with this if they actually made it a permanent change. Especially if it got reflected in Marvel's cinematic universe. Maybe Jaime Alexander could step up when Hemsworth gets tired of the role!