I can see three, maybe four of the group, as well as Andrea, not surviving the encounter with the Governor.
I'd say that Rick, Carl, and Little Asskicker are the only characters definitely safe from death (Rick is the main character, and Carl and Judith are just kids). As the conscience of the group, Hershel is probably also safe, and will likely stay that way until a new white-haired old man is found.
Because Rick has two deputies, and Hershel, being one, is likely safe, Daryl has to go. He's a fan favourite and has become a core part of the group, which means that his death will have a huge impact. His departure will allow Michonne to step up (or maybe Tyreese, if he sees sense).
Glen also has to go. He's no longer the scared kid he was in the first two series, having grown into a soldier. Maggie will probably be the end of him - either him trying to sate his need for vengeance, or protecting her (who may in turn be protecting Beth and Hershel).
With two of the best fighters gone, it also gives the writers another chance to write Michonne and Tyreese into the group (and opens up to main cast spots that recurring characters can fill).
Merle needs redemption, but I don't think he'll be given story arc time, which means the only way he can get it is to be the one who finishes off the Governor (or at least contributes). Merle's most poetic conclusion would be for him to save Rick, giving Rick the chance to end the Governor.
Finally, because I doubt Daryl will go in open combat (he's not going to get picked off like Axel), his set-piece will come after the death of Carol (maybe to a herd?). Together, they might both save Little Asskicker.
On the Governor's side, Andrea has to go, the soldiers on the wall have to go (the woman who hates Andrea and the guy who was going to shoot the people in the car trying to leave), and the Governor has to go (even though a small part of me thinks he'll slink off to lick his near-fatal wounds and pop up again in a couple of series time).
I'm not sure about Milton. He'd be useful in turning the prison into somewhere people can actually live, but I have a feeling he's going to be killed by someone to negatively add to their characterisation (for example, if Shane was still around he'd be the one to kill Milton) -- maybe in an attempt to soften the blow of a death.
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I can't see Morgan coming back as a recurring character. He served to introduce us to the world, and the event that ripped families apart, in the first series, and now he's been used to drive the point home that everyone is going crazy.
You could probably say that his use in the first series was to give us a mirror for Rick, and now he's being used as a mirror for the Governor.
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After such a terrible track record, I
have to get at least one prediction right!