Why not? Just look at the right charts. Think Tetris, Guitar Hero, 2048 or any of the many successful “bird” games for example. While one should be realistic enough when it comes to money, it’s not a bad thing at all to go for the top when it comes to game design - just pick the right market and don’t look at AAA games. But writing the design document for the next Flappy Bird isn’t any more work than writing the design document for the next complete waste of time 
Try Jesse Schell’s “The Art of Game Design: A book of lenses” http://www.amazon.com/The-Art-Game-Design-lenses/dp/0123694965
Also try searching “game design document” with google.
And one recommendation if you start with a design: always, always, ALWAYS start with a Mind Map and work the structure of the document and what you can come up with for each topic from there. Mind Mapping software is the holy grail of what was once the darkness of total game design chaos with post-its and white-boards
One last thing, while game design documents certainly won’t go away anytime soon, whenever possible I don’t make or use them. I usually stop with the mind map. GDDs are just too heavy and from my experience, nobody reads them anyway. At least not the people who should and pretty much never after the second update with changes ;). So whenever possible I use what is called a “One Page Design”, which is a huge poster with pictorials explaining the game, just like the instructions that come with IKEA furniture. Pinning this poster right in front of everyone involved with the game rises the awareness to actually read (look) at them from 1% to 99% from my experience. (And if you ever work with clients who don’t know anything about game design, like designing an advertising game for the marketing campaign of a fortune 500 company, they LOVE the presentations of one-page-designs and feel like they are game designers now right away ;))