Animal Farm/WMG

Mr. Jones used to be a pig.
The ending of the book is vague, but one interpretation of the strange events taking place then -- one of the more straightforward ones -- is that in the climax of their corruption, as the pigs are making their alliance with the humans and officially make the farm just as it was before, only worse (even re-renaming it back to "Manor Farm"), something wondrous and terrible happens: the pigs turn into men.

Or perhaps it happened shortly before that final meeting. Whatever -- it happened!

Think about this for a moment. It is quite possible that this is not the first time it happened.

Mr. Jones, the old owner of the farm, was a pig himself. Just like Napoleon, he served a cruel human owner until one day he took part in a great rebellion. Just like Napoleon, he rose from the ashes as a horrible dictator. Just like Napoleon, he turned into a human in the end as a sort of wicked prize (or a punishment) for his evil.

Manor Farm is cursed. It exists in a cycle of pain that cannot be broken. Every time the human owner grows too cruel, the animals rebel. Every time, one of the animals inevitably becomes an evil dictator. Every time, this animal is transformed into a man, and the cycle begins anew...

Ever wondered why Benjamin the donkey is so bitter and cynical about the whole thing? It's because he is really, really old. He saw the same events happening before, perhaps more then once. The result was clear to him from before the beginning.
 * That makes a disturbing lot of sense.
 * This actually fits in with the allegory somewhat. Some historians say that many countries were trapped in an endless cycle like this one; the oppressive ruling class eventually does something that causes the working class to snap and rebel, then the strongest of the working class jump into the power vacuum. Eventually, they become exactly what they fought against, and the original government is re-established (or something very similar to it, at any rate). The cycle then repeats.
 * This makes perfect sense when you consider 1984's description of the cyclical nature of revolutions and power struggles.
 * Though this is Jossed in the 1999 film adaptation, where it is mentioned that Mr. Jone's father once ran the farm, and judging from the dialogue, he treated the animals a lot better.
 * Doesn't fit the allegory, though. Farmer Jones is the Czar, and the Czar always was, well, a Czar.
 * Well before the middle ages Czars used to be nobodies.

Modern day Animal Farm
It would be back to being run by humans in cohabitation with animals, but there would be nostalgia for the Napoleon-era days of Animal Farm, particular since the leader of the animals would be a dog descended from one of Napoleon's bodyguards, and presumably had probably guarded him or his successor himself before taking over.

Yes, I did just suggest Putin was a dog.
 * Given that the most recent film adaptation ended with Manor Farm collapsing into ruin due to Napoleon alienating many of the larger animals into fleeing the farm and spending all their income from trade on luxuries for the pigs instead of necessities for the farm, followed by the surviving animals (including some of Napoleon's dogs) swearing to not repeat the mistakes of the past after a new human family buys the land, it's possible.

Benjamin the Donkey is a Time Lord

 * Because every work of fiction has to have at least one, and it would explain his implied longevity.

Snowball is Trotsky, Napoleon is Stalin, Benjamin is Soviet Jewry.

 * There, I just solved the mystery for you. You're welcome.

Snowball is America in general
He is previously thought to be a hero, but later demonized. Sound familliar?
 * Mr. Pilkington seems a more likely candidate for the role, especially with the card feud at the end.

Napoleon became Big Brother
After the book ended, Napoleon continued his hunger for power and formed the Ingsoc Party with Mr. Pilkington and others to take over Britain. Napoleon poses as a man known as Big Brother.