Is this thesis statement based on a comparison of Homer's Iliad with the film Troy any good?
The film Troy and the Lilad were both amazing, but however the film Troy didnt quite match the Iliad because of advertising , money and the need to keep the audience entertained.
This I think is a good start. However, what you need to do in order to develop this thesis statement is to make it more relevant to Homer's original text. The only items you have mentioned in your thesis statement that it seems you will talk about in your essay are relevant to the movie. There are none that you mention that are relevant to the original text. Instead of approaching it from a negative point of view, what aspects of the original text make it better and superior to the film? You need to mention both texts equally.
You might like to think about the reference to the gods, the action scenes, the use of Homeric similes and the way that the conflict is presented. Certainly, the film is more visually appealing, but does it have the depth of the original? Also, to what extent is the film accurate to the original text? What does it add/take away? What is the impact of these changes? Considering such questions should help you think through the differences between these two texts and to develop a more focused statement that identifies what is good about the original rather than merely what is bad about the modern-day movie version of the story. I hope this helps.