I prefer the command line as well; you probably realize that .
But most admins on these forums probably feel a lot more at home from the DA interface.
albatroz,
I don't know why you'd have to restart DNS for that to happen, but I do know that deleting a domain doesn't (or at least didn't, in prior versions) delete the DNS zone.
And if the zone still exists you've got two problems...
First, if the domain is hosted elsewhere and you use your own server for DNS resolution you can't send anything to that domain.
Second, DA won't let you add the domain again because searching the DNS zones is how it determines if the domain is already on the server.