“We describe it in a lot of ways as sloping the floor towards socialization, without putting a requirement on it,” he continued. “I would say that there’s some sort of – if you wanted to talk about it in MMO terms, you’d say ‘end-game activities’, but some of the most intense non-competitive activities in the game do require cooperation. They require a group of players to tackle at once.
“I guess at some variable, distant endpoint we are going to say, ‘Yeah, if you show up at this door, and you don’t have five friends, you’re not going to be able to succeed,’ but the core experience that solo players have enjoyed in shooters, they’re going to be able to get that, and we’re going to pull many of them into social experiences as well.”
So, it sounds as if it won’t just be a case of these missions being too difficult to tackle alone, but rather that being part of a team will be a requirement. If you were planning on playing the role of a nomad, this might come as a bit of a blow.
Update: Urk from Bungie has clarified. Please read this before responding:
Looking at the article, it's super clear why people are confused (and agitated). The OXM article states can't complete "missions" without playing co-op. Jones never says that in the GI interview. He specifically and explicitly is speaking about "end game activities," "the most intense non-competitive activities."
Missions, of course, heavily implies story/campaign. You aren't required or forced to play any story missions in Destiny as part of a co-op group.
Make more sense?