The blockchain NS setting is set by default to namebase's nameservers which is a nice convenience, but it would also be convenient to allow users to define default DNS entries to apply for all new domains automatically, so that whenever the name comes out of auction it is immediately "live" without needing to do any tedious followup. I think the typical use case for this will be to point to a "coming soon" or parking page but could also be handy for when a collection of names are used generically for similar purposes or just hosted in the same place. It would also help boost the number of handshake names that are visitable in browsers