I feel that the most glaring weakness of Asana is the lack of any defined options to establish a project hierarchy. Currently, the only way to group projects is by establishing teams (if you are a premium user). However, even that can get very cluttered.
When kicking off a large projects, it would be fantastic to break it down into multiple sub-projects rather than sections. That will reduce clutter and allow users to hone in on sub-projects. Currently, sections, though useful, are not collapsible, so projects can get very lengthy.
Furthermore, a user should be able to drill into a sub-project and see a defined breakout of the sections, tasks, and subtasks.