Hathor--special needs is a huge priority for schools. Its management and oversight is controversial, the students are either heroes or terrors, depending on your POV. But they do have a compelling journey and--if told right--will have readers cheering for them. I think there's a considerable market for it. The problem is--do editors and agents think so. We're all struggling with that. The key is to make a compelling enough case that they can't ignore it.
Ancient Sparta--well fantasy is coming alive again, thanks to Game of Thrones on HBO. True, Sparta isn't fantasy, per se, but much of season one of GoT isn't Lord of the Rings style fantasy. Its gritty realism. I picked up two books at BEA based on the ancient world--one about the Mongols and one whose story escapes me. The point is, publishers are putting it out. My guess, though, is that it has more to do with the underlying theme than the setting, or even genre.
Look at Harry Potter. Strip away the trappings, and what's the heart of the story. It's not about magic, it's an orphan boy's coming of age story--how he finds friends, learns to belong, and ultimately obtains peace and happiness. The Hunger Games is about oppression. It's no accident that children take center stage. They are the most vulnerable and powerless in any society. Granting them the power to overthrow a regime--that's psychological genius.
Shoot my own story, with all its big actions pieces, power-wielding gods, etc, is essentially about making choices, owning up to the mistakes, and accepting the consequences. When pitching, we all need to boil things down to those elements and present them in a gripping manner. Everything else, really, is window dressing. Insanely cool and beautiful, to be sure
, but window dressing all the same. Right?