Add title & subtitle to shortcodes

function spoiler( $atts, $content = NULL ) {
    extract( shortcode_atts( array(
        'title'    => 'default title',
        'subtitle' => 'default subtitle',
    ), $atts ) );

    return '<div class="moreinfo"><h3 class="click drop subtitle">'

    .'Title:'.$title.'Subtitle:'.$subtitle.

    '</h3><div class="morecontent"><p>'

    .$content.

    '</p></div><!--/.morecontent--></div><!--/.moreinfo-->';
}
add_shortcode( 'spoiler', 'spoiler' );

//[spoiler title="title" subtitle="subtitle"]content[/spoiler]

Docs: add_shortcode, extract

That should allow you to display the title and subtitle by applying them as attributes. You could, if you liked, do processing on content and use some sort of divider (say || or something that would never be used in the text) and do an explode() on the content based on that divider…your call.