I still really don't understand it. From the press junket Aaron says "This is the THOR of the Marvel Universe" making it seem like when this female Thor shows up that there on within the Marvel Universe it will be as if Thor was always a female. I think Marvel just needs to say if this is a new character completely or that it's essentially retconning male Thor's existence.
Honestly I don't have anything against it, but the way Marvel is handling it makes it seem like they just want the press. I mean announcing it nearly 4 months ahead of time make it seem like they just want headlines all over the web. What they should just be doing instead of this is give Sif her own series again and promote the hell out of it. Her Journey into Mystery was so much fun and I think it could catch on if Marvel was 100% supportive of it and trying to establish her as one of Marvel's strongest female characters.
Either way I haven't been reading Thor as he's a character that I'm not that into. I enjoyed the first volumes, but it's nothing I want to get monthly.
Female Thor? How about instead promoting your already established awesome female characters? Lady Sif and Red She-Hulk had awesome series' that no one read. Give those two another chance and promote the shit out of it!
It kind of feels like the only reason this is happening because Thor is one of their most recognizable characters and can get them headlines around the web.