For me it's not a top priority.
Musing questions and answers are typically short. I write each answer in one sitting so the need to save and come back at a later date feels unnecessary.
Even when my internet drops in between starting an answer and posting it I haven't lost the answer. I just reconnect and resubmit.
I think that there are more important developments that should take precedence, such as a new system to determine the top answer, improved structuring of the question list, removing duplicate questions etc.
So while I'm not against the idea, I just wouldn't want the devs to focus on this before more important changes.