I don't know if this has been posted yet but I played the game for 5-6 hours at a friends house today and the 69 missions are the main storyline however strangers now count as separate missions as well with completion goals and medals. Strangers can also have more than one mission for the player, one of the strangers I met had me do three missions for him. A good few of these are full missions.
So missions so far are the 69 missions that are part of the main story. There are 20 strangers/freaks in the game. Each of those strangers have at least one missions but most of them have multiple missions with an over arching story-line for each stranger.
So main missions plus strangers missions gives us 89++ missions at the very least.
Stranger missions are also more in-depth than GTA IV and those I played were proper missions.
I'm sorry if this has been posted already but I figured it was worth sharing for those that didn't know.