I predict that Whitebeard will take out at least one Admiral in this upcoming rage.
Why? Because he's the world's strongest man; because he's pissed; because they will be the only match for him; because there needs to be an empty spot for Coby to become an Admiral; because the Marines need to suffer at least one major loss in their forces (My guess? Aikinu).
Whitebeard will actually be winning, but thanks to Blackbeard's arrival he will BARELY fail to rescue Ace, and be killed.
I don't think he'll take an admiral out, especially Akainu, who I see having a bigger role in the NW (and I predict a fight with Dragon). Aokiji obviously wont die. If anyone does, it'd be Kizaru (as I don't see much background or controversy around him) however I don't think he'll die either.
Whitebeard will die, making it a big loss to the pirates. And I think Garp will die, making it a big loss to the gov't. However I think that Garp may choose his family over his role, which would mean Whitebeard wont be the one to kill him.
So what I think is that Whitebeard will kick some ass (maybe take someone big down, but surely take out some giants or VA's, and even maybe a Shichibukai; Moria). Whitebeard will start to weaken due to the stab and fighting the admirals, and Blackbeard will turn up and do something random leading to Whitebeard's death (Oda will not make WB's death predictable at all).
And Garp will die by sacrifice (after witnessing the death of Whitebeard).
Whitebeard will do enough to see the rescue of Ace, and Luffy will be the one to take advantage of Whitebeard's attack and grab Ace (he has the keys). Whitebeard will see Ace being rescued as he dies (and while he dies he'll order everyone to run off and leave him).