I think the options in dumpxml is nessary.
[root@yds-pc virt]# virsh help dumpxml
  NAME
    dumpxml - domain information in XML

  SYNOPSIS
    dumpxml <domain> [--inactive] [--security-info] [--update-cpu] [--migratable]

  DESCRIPTION
    Output the domain information as an XML dump to stdout.

  OPTIONS
    [--domain] <string>  domain name, id or uuid
    --inactive       show inactive defined XML
    --security-info  include security sensitive information in XML dump
    --update-cpu     update guest CPU according to host CPU
    --migratable     provide XML suitable for migrations

There are lots of options for the dumpxml cmd, So I believe the param added to virsh.dumpxml is worthy.