I prefer to call it a "not yet" than an oversight; so far only DOM Level 1
is available. There is lots of work yet to do, including standardised ways
to read documents, serialise documents, validate documents, .... ideas on
prioritising all of this are welcome, but I'd suggest you send them to the
public DOM mailing list (www-dom@w3.org; to subscribe, send email to
www-dom-request@w3.org with the subject "subscribe").
cheers,
Lauren