Hi,
I cannot reproduce the issue you describe about creating child pages when logged in as a user in Content Authors role and the page has edit and create child permissions for Content Authors role. I tried to produce the issue on my local machine and also on demo.mojoportal.com.
Any other information you can provide? Is it a child site? Using host or folder named sites?
At some point I do plan to make it possible to define which roles can use which features when adding content to pages. Currently it is possible from a feature definition file to make it AdminOnly but it doesn't currently have support for availability based on roles.
Best,
Joe