In my experience, unless you have a significant demo-able product already, a significant population interested in your progress or a strong history in profitable games, no investor will touch your idea. Unless you already have one of those things or more, you might want to skip the Business Plan, and focus on marketing for Crowd Funding sites. More investors are interested in hopping on board an already successful operation, than an idea. For instance, start your game small, and start taking in some kind of revenue, however small. Then add one or two features, and track how the finances increase with that. Then present that information to potential investors with an idea showing how the next feature needs some additional capital to create, and based on the history of the game will introduce X percentage increase to profits/customer count.
Investors tend to be experienced enough to recognize the difference between projections based on facts and projects based on guesses. especially with the financial climate the way it is, you'll be hard pressed to get any investor on guesses.
Crowd funding is very different. Typically, you establish goal levels, I.e. at 10,000 the game development will begin. at 50,000, we will contract out to highly professional artists. at 100k, we blah blah blah. then offer things like getting a good feeling about helping the product by giving 5$, getting a free online membership for the first year, for 15, (anticipating 20/year cost), and 100$ for unlimited life time on the server, etc... Check out whats already out there, what worked and what didn't.
Moltar - "Do you even know how to use that?"
Space Ghost - “Moltar, I have a giant brain that is able to reduce any complex machine into a simple yes or no answer."
Dan - "Best Description of AI ever."