I really don't think it's going to be completely set in a new Galaxy. Old characters potentially returning was mentioned in NerdAppropriate's tweets, so I think (and really hope we're staying in the Milky Way).
Honestly, what I need right now is for one of the devs to reassure me that this is going to be a Mass Effect game. That even though the Mako is now a Salarian land-rover with no guns, even though Shepard is gone, that this is going to feel like a Mass Effect game and that instead of drastically changing everything they just build upon and improve.
Also, let us walk around the whole of the Citadel now pls.