Well, I think there are a number of answers that could be given to this question, and you might want to think about transferring this question to the discussion board so that you can gain a wide range of opinions. However, for me, in spite of the allegory of the Russian Revolution, this novel is timeless because it discusses explicitly the nature of tyrants.
Generally, this novel is a satire of politicians, particularly focussing on their rhetoric and their ability to manipulate others and the way that once they gain some power they have a compulsive tendency to gain more. Note how Napoleon is overtly presented as having altruistic motives, yet it is clear he is a power-hungry individual who manages to cover up his self-serving actions with the excuse that he is only doing them for the sake of the farm as a whole. Just one example is when he steals milk and apples and then says that pigs need the nutrients contained in these foods to carry out their managerial work. Note how the removal of Snowball is explained by the revelation that Snowball was a traitor. The Seven Commandments are regularly transgressed by a manipulation of language, and whenever the farm suffers a setback, it is Snowball who becomes public enemy number one and is always blamed. Clearly the ending of the story, when Napoleon becomes to all intents and purposes like just another human, reveals the tendency for those who ostensibly espouse the most virtuous ideas to become the worst enemies of the people whose lives they are claiming to improve. You only have to look at any number of dictators around the world to see that this is true, unfortunately.