This all can be generalized into a compact identity transformation that copies all the nodes to output.

You can specify the identity transformation with xsl:copy:

<xsl:template match="@*|node()">
  <xsl:copy>
    <xsl:apply-templates select="@*|node()"/>
  </xsl:copy>
</xsl:template>

Keep in mind that other match patterns will have higher priority by default.