Panels doesn't output views content pane title
The $title variable for the views_view theme hook is added only for the administrative preview. Here is the section of code in template_preprocess_views_view() that adds the title: http://cgit.drupalcode.org/views/tree/theme/theme.inc?h=7.x-3.11#n85

If you want to add that variable to your template override, you can do so with an additional preprocess.