The catchphrase if you will for destiny is. "Become legend" is it not? If not than something very close. In saying that led Zeppelin are considered a legendary band, I understand the idea behind putting this song in the trailer, but yes you're correct in saying the music doesn't fit well with the trailer. I personally think the composers in the bungie team make excellent music which it shown in Destiny and Halo, surely they could just make a piece of music that fits the trailer more appropriately.