I have a new droplet based upon youtube's new iframe code. Try this:
if (!$H) $H=300;
if (!$W) $W=500;
return'
<iframe title="YouTube video player" height="'.$H.'" width="'.$W.'" src="http://www.youtube.com/embed/'.$YOUTUBEID.'" frameborder="0" allowfullscreen></iframe>
';
Usage:
[[yt-embed2?YOUTUBEID=HtJc9xKn8cY&H=400&W=600]]
-- or you can use it without the variables --
[[yt-embed2?YOUTUBEID=Y_hQORwUMn4]]
Let me know if it works for you.
Jonathan