I think that each of the animals' in the book represents some level of Orwell's perceptions of life after the Second World War. His perceptions of the corruption of Socialist thought in the hands of those who wished to consolidate their own power helps drive the purpose of the work. I think that his fear of how Communist regimes twisted Socialist ideology might be why Orwell could have identified with Boxer to a great extent. The strongest animal on the farm and the most loyal, Boxer seems to me to embody Orwell's greatest fear. Boxer's constant devotion to the state and its leaders, his tireless efforts to protect the farm and "work harder" as well as his faith in government is what ultimately kills him in the end, as the state to which he holds the greatest of devotion denies him any justice as it betrays him. It seems to me that Orwell writes with him in mind, and the millions of other "Boxers" who are at the whim of their own governments.
I would say that the animal that comes closest to representing George Orwell's own point of view is Benjamin, the old donkey.
Benjamin does not have any great hopes for the revolution or, really, for anything else. He believes that, no matter what, things will pretty much stay the same for the animals. If they are not being exploited by Farmer Jones anymore, they will be exploited by Napoleon.
Orwell clearly is saying in the book that the animals are no better off after the revolution. Of all the animals, Benjamin is the one who makes this point more than any other.