Inside the Project list page (in the Admin area), you see a list of projects with the column 'Default Assignee' and 'Project Lead', but the 'Edit' button on that row doesn't let you change those values. To change that you'll have to access the 'Roles' page of that project, inside the project admin' area. It's quite unintuitive for customers.

For instance, the 'pencil' button that you have to click inside the 'Roles' page of the project to change the 'Default Assignee' or 'Project Lead', could be on the Project list page, right next to the respective value and could redirect the user to the 'Roles' page of that project. I think we would have something like that: