I think that in small midsize organizations the need to have a full featured DNS server (authoritative) was unnecessary, even in other platforms this is happening.
At the other side, in specific cases (but I think in bigger organizations or at least in a more articulated scenario) the administrator should have the chance to install a full featured DNS server module/package as well as the chance to easily configure what he needs through the GUI.
IMHO I think that NethServer fits better where there is no need of a full featured DNS server.