Rewrite the markup of panels page title
Following the comment on the panels issue linked in the question, I managed to make the panels page override for term_view works.
This is the code added to mytheme/template.php

function MYTHEME_preprocess_page(&amp;$vars) {
  // if this is a panel page, add template suggestions
  if($panel_page = page_manager_get_current_page()) {
    // add a generic suggestion for all panel pages
     $variables['theme_hook_suggestions'][] = 'page__panel';
    // add the panel page machine name to the template suggestions
    $variables['theme_hook_suggestions'][] = 'page__' . $panel_page['name'];
        if($panel_page['name'] == 'term_view' ) {
           $vars['theme_hook_suggestions'][] = 'page__term_view';
}
}
}


Then, inside the mytheme/templates/ folder, I added page--term_view.tpl.php with my custom page title display.