What is likely happening is all of the titles are being relaunched. NEW AVENGERS will likely just become "THE AVENGERS" and Bendis will write that, with the big three on it. To be fair, his original New Avengers line up had Cap and Iron Man in it, and he has Thor now instead of Sentry. I imagine Spider-Man, Wolverine, Luke Cage, and Spider-Woman would remain and fill out the cast. Bendis may finally have a chance to tell whatever stories he wanted to tell, without having to shift away to pretend he was always alluding to stuff like SECRET INVASION or whatnot. That is, he doesn't have to deliberately leave gaps in his stories to be filled in later. Least for those who like his stuff.
I imagine Christos Gage's AVENGERS: THE INITIATIVE will be relaunched; the main rumor is something called "AVENGERS ACADEMY". This is perfectly fine; the X-Men seem to always have some junior team hanging around in print, whether it is called New X-Men, New Mutants, Generation X, Academy X, or whatever. Why not the Avengers? Sales on that book have slipped since Slott left, even if the quality actually improved (an amazing feat), but it still will likely last 3 years within the Top 75 despite only starring B, C, and D list characters; to Marvel that has to be seen as an accomplishment, worth at least one relaunch stab.
The biggest question mark is Dan Slott's MIGHTY AVENGERS. The whole gimmick of the post-SIEGE era is to reunite the "classic" Avengers, but some could argue MIGHTY AVENGERS already did that in a way. The only "new" characters on that team are Amadeus Cho (by virtue of being Hercules' sidekick), and Stature & Vision Jr. from YOUNG AVENGERS (by virtue of Vision being Vision, and Stature being a legacy character). Considering the line up, it really is AVENGERS WEST COAST by another name, but editorial seems to dislike that name. Of course, this is the same editorial who thought calling a mini series "MARVEL DIVAS" was a good idea and then were stunned it failed to catch on.

With sales slipping on MIGHTY, it could do with a relaunch to spike things for a month or two. The riddle is what to call it, if MIGHTY AVENGERS won't just be repeated. NEW MIGHTY AVENGERS?
Marvel could just merge Bendis and Slott's titles into one bi-weekly AVENGERS book, much like AMAZING SPIDER-MAN merged ASM alongside it's two other side titles, but that has been more of an experiment than a changing of the guard in terms of strategy. If Marvel won't merge their X-titles into one book, they certainly won't for the Avengers. I mean hell, Deadpool at this point could be merged into one book.
I plan on ignoring whatever Avengers title Bendis is on. I read his NEW AVENGERS well over four years and my reaction to it went from disappointment to annoyance to loathing to outright dread. For every issue that Bendis wrote that was even mediocre, he had another issue that was either terrible, or some long winded lecture about some character or genre convention disguised as a story. NEW AVENGERS continues to be the most overrated thing on the racks. While it has done wonders for Spider-Woman and Luke Cage, Spider-Man has become more of a laughing stock since, and Wolverine's been of no consequence. Bendis also has no ability to write Thor or many other high powered heroes. When he tries to amp up a character he likes, like Hood, he shows no patience to do it right and instead goes for Chapter 10 before he properly finishes Chapter 2, making the transition awkward. He has some solid ideas, but little idea of how to efficiently execute them. That hasn't changed, and unless SIEGE really surprises me, it won't just because of a new #1 and a new title.
Dan Slott is a gold mine for merging old school continuity with new story angles; like a Kurt Busiek with more of a sense of humor. His MIGHTY AVENGERS has gotten better as it has gone along and has done wonders to redeem some characters such as Hank Pym and Quicksilver. He gets that the Avengers are about sun drenched heroes taking on larger than life threats, instead of ninjas in a hotel room. I certainly want to see him on an Avengers title longer than a year and a half.
Christos Gage has been Dan Slott's co-writer for a while at times, and he often makes Slott's stories even better at times. But since taking over for AVENGERS: THE INITIATIVE over the last year, he's made that book into a must read every month. He has a talent for plucking any character from the Marvel Handbook, whether a B-List New Warrior or a Z-List "who's that" character like Johnny Guitar and write them excellently with however much time they have per issue, whether 10 pages or four panels. Characters that other writers would just insert for a punch-line or an expendable body, Gage understands and tries to do justice to. His work seems under appreciated at times, as he also usually does some random side work for the crossover du jour, but he often can make a generic story seem exciting by execution. As much as I would hate to lose MIGHTY AVENGERS every month in some form, I would also hate to lose AVENGERS: THE INITIATIVE. I mean, where else can you expect characters like Justice, Tigra, Constrictor, Taskmaster, Prodigy, and so on to show up and be used well?
Right now, I read MA and A:TI and skip NA. They can retitle, renumber, and relaunch them, but I'll still read the Slott and Gage books, and skip Bendis'.