- Let people upload cover art: This will let people who have decent design chops/family in the business/etc. Stand out a little more. And as Amanda Hocking's books show the cover can be a stock image with a genre appropriate font well within the means of anyone with PowerPoint.
- "This + That" pitches: I know some VCs and Hollywood types love this format e.g. Alien is "Jaws in Space". What if you could pull in a couple images from Amazon to illustrate that this pitch is for a book that is sort of like "Game of Thrones" meets Robert Ludlum.
- Author photos: let the authors make connections with the sponsors. Let them tell their stories "I'm a stay at home mom who has been dreaming about this book for a decade"
- Rewards: Galley copies if it gets published, Buy the "For:" in the front, etc.
A talented author can build a fan base anywhere, but it's easier where there are already potential fans. This site looks like there are six (6) story pitches total, and probably as many users.
I'm not knocking the idea, I'm asking what you intend to do to compete with the incumbents. "Different features, more focus" is not sufficient.
I think you should go vertical and integrate with something like OpenCalais for subject-matter tagging which you can use as the basis of a recommendation engine, and some sort of document-based CDN.