I work in the entertainment industry. 17 years now, in fact. Unless you're working on your own project, it's someone else's vision / voice you're working on. And as a professional, you have to have a compromise with having your own input and what the client (ie the one paying for it) wants.So you think that your convictions as a "good" artist count for nothing and that it's all just business?
Well, you will certainly have more in your bank account, but that is the only satisfaction you will get out of it.
Remember, just because someone pays you for your labour doesn't mean they own you or your craft, and that's why we also need well-drafted contracts before such a project can even get started, so that each participant knows where they stand and exactly what is required of them; in this case explicit drawings of course.
And I'm sure if this had been done properly, they certainly wouldn't be in the position they are in now and wouldn't have to do the artwork all over again.
It's ultimately their name that's on the project and they need to be happy with the product. Your wants / artistic desires / religious beliefs / ego takes a back seat.
From what I gather about this project is that this was always going to be an issue from the start.