This show kicked ass in ratings last year, and CBS and MB had no reason to think it wouldn't do just as well this year. MB and CBS would not do something crazy to the show, like a 3 tribe think, or an early merge. If it ain't broke, don't fix it.
So, what is the Twist then?

Remember that MB and CBS are prone to hyperbole. I can't even count the number of times we were promised an episode of mammoth proportions, only to get some tiny bit of drama.

Just this season, the Buffalo and Lion scares turned out to be a few seconds of very tame footage.

When they say "All alliances/friendships are broken," they MUST be exaggerating. There is simply no event that could break all alliances and friendships short of killing off all the contestants. Beware of the word 'ALL,' it always is a signal of exaggeration.

I think that some sort of temporary swap, similar to the 'girls/boys night out' thing from last season, is the only viable option here. A swap like that could easily put a crimp in alliances.

FOR EXAMPLE:

Frank visits Boran and gives them voting details, making Lindsay and Silas feel vulnerable, but Kim P and Brandon feel safe. Maybe Kim P. and Brandon begin to question the wisdom of staying alligned with Lindsay and Silas.

OR

Kelly visits Samburu and becomes best friends with Kim P., making Brandon and Lindsay jealous.

There are any number of things that could happen from a temporary player swap.

A temporary swap would not violate the rules.