Old Major had a dream about a new society in "Animal Farm". Was it a realistic one? Were his theories weak?
I don't think his dream was a realistic one for several reasons. After reading the novel, you can see some of the pitfalls he failed to see. He assumed, as many of the American Romantics did during the 1820's, that the animals were all basically good and could work together to form a society where each animal received according to his or her need. Instead, you can see that the pigs are power hungry from the beginning and the workers range and animals like Mollie, who wants only pretty ribbons and little work, to Boxer, whose motto is "I will work harder." Old Major's vision failed to consider the basic instinct of animals---self-preservation and self-satisfaction. Thus, the revolution as seen by Old Major was flawed from the very beginning. The lesson learned from this can be applied to the human Russian Revolution and even the French Revolution. The reason the American Revolution eventually succeeded was because the founder were more realistic about human nature. They realized the desire for power and greed was very strong and so they instituted a Constitution which included separation of powers and checks and balances against any group which tried to be too powerful. Orwell's message is a true today as it was when it was written over 60 years ago.
First you have to ask yourself the question of what Old Major's dream was. What was his vision for the animals, not only on Animal Farm, but throughout the world (England.) Is it possible to have this type of society? Why/why not? (The answer lies within the story itself - what happened to the animals?)
As for his theories - look at Old Major's speech again. You could argue either way.