Right now once a to-do is created, if it has to be moved under a different activity, master activity etc, it has to be deleted and created again under the correct record. I would suggest making it possible to change the to-do's affiliation without deleting it.
We have 2 use cases:
A set of To-dos need to be moved, from 1 Feature/Activity to another, or to an Epic/Master Feature.
A Feature/Activity (with or without To-dos) needs to be moved to a different Workspace. Ideally the To-dos come along with the move, along with any Comment history.