I think their whole stance on the weekly heroic, nightfall, and raid was you are suppose to gather your fireteam and complete the challenge with that fireteam. I believe early on when VoG was only talked about I read that whomever your fireteam was was the fireteam you had to do the raid with. Meaning every member was locked in to that group. They caved a bit and gave us all check points where if needed we could start up with different people and they caved again by giving us matchmaking for the Weekly heroic. But I'm with you, they have not given the community what it needs, which is matchmaking for all content. I'm also with you that it should be fireteam or open match so that you have the option to do the nightfall or raid solo, you and your friends, or fill the fireteam.