Any speculation of this nature is just a way of killing time, really - they could make a brick of Maiden Backs and call it a day if they felt like it, and there's no set criteria for what they do and don't include. The first one or two Variety Boxes had a genuinely good line-up - and the one-of-a-kind Vintage version was killer - but beyond that, they've been pretty blah. At most they toss in one or two worthwhile and hard-to-obtain decks and the rest is filler.
IAOCP has been in a few boxes already. I'm thinking they won't include it anymore. MCv2 is practically guaranteed. Bee "Watermelon" RJRTC decks are also not likely since they've appeared a few times before, to my memory. If S&M v7 is out by then, it's a strong contender for a slot. Aladdins have been in way too many of them, and Studs are a little too low-end; it would be like putting Standard Rider Backs in. Sentinels are possible, since they're in re-release now.
New decks that might make an appearance:
Bicycle Americana
Ornate (when it releases)
Mana
Seasons (some will get Primavera, some will get Seronda)
BeDeceived Style
Bicycle Spectrum
the NOC deck (when it releases)
It would be nice to think they'd consider the Phoenix Apocalypse 2012 deck, but they've never added Card Shark decks before. Pr1me could be a dark-horse contender for a space in the brick.
Don't expect more than perhaps three totally new decks. It would be nice for them to surprise everyone, but don't count on it.