Along the same lines as having a default name for new posts, an option to include default content in a new inline post would help with tasks like using an inline for a comment form on each new blog post. --JoshTriplett
No, it would only help if the new blog post were being made via the form. If you're editing it in vi, and committing, it doesn't help.
This is another reason why I prefer the approach in discussion page as blog --Joey
This feature would also allow the automatic inclusion of a given template in every new post, which could help for plugins (automatically use the plugin template), or for bugs and todo items (automatically use a template that appends "(done)" to the title if the page links to "done"). --JoshTriplett