Here’s a powerful, yet not-too-complicated improvement for facilitating simple project management within Agenda: allow notes within a project to be categorized by user-defined topics. I currently create one note for communications and link all emails related to a project there. I then create a documents note and link all related docs there. It would be cleaner to have a filter that explodes under the project list by project, and it wouldn’t take a huge amount of dev time.
That’s a classic 
The way to go is to use tags in combination with smart overviews. While it’s not yet possible to then limit the smart overview to a specific project only, what you can do of course is to create project specific tags, for example projectX_email, projectX_comms etc and create smart overviews for those.