I've been monitoring what the daily heroic mission is since its release and I swear to God only one mission was the daily heroic mission. It was The Iron Tomb and it was on the second day of Rise of Iron. Most of the time it's vanilla story missions that are the daily heroic missions. This concerns me as we may not get the Black Spindle/No Time to Explain of Rise of Iron. In other words, no secret exotic weapons from the daily heroic missions.