Hi Dan,
I think @trebso already said it well, Agenda doesn’t aim to be the same thing as Things, where everything is focused on tasks. You can use Agenda as a task manager, but the focus is on note-taking, where tasks are living within the context of your notes. As said, this can still work extremely well, in fact both @drewmccormack and I are using Agenda ourselves to manage pretty much all tasks related to developing Agenda and everything else going on outside too. I don’t feel I need an additional task manager like Things or Reminders at all, but of course this can be different for all of us (and there are indeed those that even integrate the two heavily).
Best is to browse around a bit perhaps in the community, especially in the Talk section, where a number of users have shared their experiences and workflows.
Enjoy Agenda!