Like some one mentioned before, its about the time you spend between level 1 and 60 that alot of people liked, the community, the people you meet along the way, the stories of being camped, trying to level in the stv warzone, all that was pretty much taken away in later iterations of the game. After ?cata? you might as well be playing a single player RPG, lfg queuing and getting matched with bots. That's what it felt like for me compared to how it used to be. So I'm all for that adventure again.
Going to SM or Dire Maul was a commitment, it made it that much more satisfying when the whole party to eventually arrive 45 minutes later and the tank was 4 levels too low and the healer was actually feral spec. But you did it any way and made it work.
It wasn't a formality, but a sense of excitement!.... And loads of time to spend that I probably don't have these days but what ever, let's do it!