Bendis has said that it will have "major consequences and has a jaw dropping ending that only five people know".
I never said it wouldn't have any impact on current continuity...but it is mostly self-contained. This is why Marvel probably made it an event series so that it would, and gave it additional tie-in series (like the Superior Spider-Man) one.
Bendis returned Janet in his last Avengers arc...but I don't think she has appeared in any series yet, doesn't mean that she won't soon though
Remember that this was originally slated for last spring or summer, but they had "Avengers Vs X-Men" as their major event book at the time, so it didn't make sense for them to have two big series out...even though they will with this and "Infinity" when it arrives in the summer time.
I've long thought this was originally meant to be the conclusion of Bendis "Avengers" run but was changed to be an event but editorial. I'm pretty sure this was first announced at SDCC 2011.