"Shared draft" as default behaviour for a shared inbox (instead of personal draft) – when creating a new conversation (via compose button), not only on reply.
Example:
we have a shared inbox e.g. "accounting".
we draft invoice emails sometimes weeks before they are send out using "send later"
currently only the person who drafted the email has this as personal draft
goal is to have mails as shared draft for everybody with access to that inbox
without the need to actively invite others to the draft