Obviously we can see by being run off the farm that Snowball was an ineffective leader.
So, he was removed by someone more powerful and therefore lacked power, but why? Why didn't anyone fight for him?
I think if you take a look at the committees Snowball tried to create and the language he used with the animals and the response they produced to each, you will find your answer. He could have been a great leader, but would not come to meet them at their point of need. They wanted to trust him, but could not understand him. You can find quotes to support these 3 claims on pages 32-34 of the Signet Classics edition of the book.
His committees had great vision, but the purpose was not articulated in a way that the animals could comprehend.