You can certainly change the map output – whether with a goal of modifying it or replacing it completely – via the tribe_get_embedded_map filter, so you could explore that avenue if you wished to do some neat new thing there.
With regards to changing the + Google Map link, you could add the following to your theme’s functions.php file (and tweak to suit):
add_filter( 'tribe_event_meta_gmap_link', 'change_gmap_link_text' );
function change_gmap_link_text( $html ) {
return str_replace( '+ Google Map', 'Directions', $html );
}
Does that help?