Character development is conflict.
Think of a pitch in terms of advertising: You're trying to hook a reader the way a commercial tries to hook a detergent user.
A novel is a big thing. It's difficult to hold the whole story in your mind, especially when you've finished a first draft and are still giddy from the flow of creative juices.
Authors worry. We worry about writing. Worry about our editors, our agents, our reviews, and our readers. We worry about everything, including all forms of social media including blogs, Facebook, Twitter, and personal websites.
Writing a log line helps you define - for yourself - the essential elements of the plot. It will also let you know immediately if major components of the plot are missing.