A JIRA like permissions scheme should be used to define permissions.
A permission scheme could then be attached to spaces.

All confluence actions should be available in a permissions scheme :

• All page operations
• browse incoming links
• browse trackback links
• browse hot referrers
• browse external references
• add blog
• modify blog
• delete blog
• add comment
• view comment
• delete comment
• administrate space
• use notation

Maybe other actions should be added