the 12 player part refers to 4-8 players making money and getting eq for the "rushing" crew - and part of that team is there to replace the main gamers while they sleep ...
torg - getting to lv 60 isn't a matter of a couple of days. From what they said during one of the interviews - it took some inner blizzard geeks about 3-4 weeks to get to lv 60. That means a power gaming crew that tries to fly through the game rather than feel it - should be able to reach 60 in about 1,5-2 weeks. I can game for like 50-60h i one frenzy ... sleep 7 h and keep going - but still 7h lose in a race is HUGE - that's where the other gamers step in
Mantas - i totally agree with your point of view. Been waiting for this game for almost a decade... and I'm gonna rush it? Well maybe nightmare and hell - yeah
but not normal... every rock, log and tile of dirt must BE TOUCHED before I can pass to nightmare!
anwsering your question: pride and pure satisfaction. it's like asking (bad example but still) why one goes up K2 .. many ppl die during that adventure.... yet some can say "I've been on top of the world" ^^ pretty corny but i think it's understandable for even the most conservative people.