I think you have written good essay. I feel that you also need to emphasize on negative aspect of the topic, in this case you may want to pick an e.g of a person who was leader by birth and further point out that he never succeeded. You know what I mean. This makes your argument strong. I feel you have biased your essay on one side. you need to bend it towards the other side and straighten it back with strong argument.
Sturcture looks good. And you have strong points. Have as many small paragraphs as possible and have logical relation/transistion if possible between them.
Well I am not an expert on writting essays...but this is what I think might help....
hope that helps..