Hi @anon18396054, welcome to the Asana Community Forum and thanks for taking the time to share your feedback with us!
We have a couple of threads related to this topic, I suggest you joining the conversation around subtasks and upvoting for these features in these threads:
- To Subtask or not to Subtask - #79 by Stefan_Jenkins
- Allow to automatically add subtasks to project
- https://forum.asana.com/t/rules-and-subtasks/70123
- Mark subtasks complete when completing parent task
I hope this helps!