I understand that Animal Farm is a satire of Stalin and the russian revolution, but I don't understand the message that is trying to tell us.
The book is about a group of farm animals that is being oppressed by the farmers, so the animals, commanded by the pigs overthrow the farmers and the animals get in control but in reality is the pigs who end up controlling the farm and they are as bad as the farmer.
So to me the message is simple: "don't revolt, don't try to change the status quo, nothing will change if you try, so don't do it"
The functional message is exactly as you describe. You could make some pretty small changes to the book and end up with a much better (albeit still Trot) conclusion.
One thing I really love about the Hunger Games -- really one of the only things I like at all about it -- is
spoiler for the very end of the third book
Katniss, at the execution of the old dystopia's leader, just fucking murders the leader of the rebellion because she recognizes that the leader is a power-hungry monster. The rebellion already succeeded and the old leader dies later, so it's not counterrevolution so much as a purge.
I think a better version of Animal Farm that maintains Orwell's professed ideology would have a segment of the animals attempt a revolt against Stalin Pig and, because the other animals didn't join them because Stalin Pig is a hero of the revolution, get crushed. Then the moral could still be pro-revolution while being anti-Stalin in a way that is, if anything, much more pointed. Still mistaken, a slander of Stalin, and anti-communist at heart, but at least better.