In the past months I have explored way of pushing asana, and I have been working a lot with subtasks. It is great that a subtask can be assigned to multiple projects, as it offers a huge flexibility.
Now, it would be absolutely awesome if a subtasks could be a child of more than one task!
Let me give you a specific example: I use subtasks to keep track of things I have to do for specific events. If the event has one client, then it is simple for me, as client > event > task.
The challenge is if the event has more than one client, or party, involved. It would be ace if I could have this:
client1 > eventA > taskX
client2 > eventA > taskX
Coming from a nerdy background I understand the implication of inheriting from multiple parents, but it would add a layer of flexibility to asana that would allow people to generate complex and flexible templates at the same time!