More teanwork, the lesser the team?
I have spent more time doing 2 v2 in the past month or two, and I have come to notice something. In random pugs of 2 v 2 my teammates are more active and actually try communication then in 3 v3. In more 3v3 I noticed my teammates never talked, never asked for help when they needed it the most, never let anyone know they are about to retreat or even when something couldn't be done. While in 2v2 I found that me and my teammates would get into discussions on who does what and when, who to focus on, and so on.
Does the fact there is one extra rogue element change the scape of the game completely making the team think they won't have to get anything because the other person will do it? Or is it just because in a 3v3 you are more likely to have horrible teammates who just won't listen and think the game is about chase down and kill everything in their path.