The leveling system does suck. You do fetch quests and go to X place quests, and kill a bunch of mobs. Not really anything to write home about if you're doing it alone.
But I like the older dungeons, the quests there, and some of the zone aesthetics in sub-60 vanilla. Yeah, it's a grind. But you'll find others on the same journey as you, team up with them for an elite quest or dungeon, recruit them to help gank that horde that killed you when you were at 25% hp and fighting a mob. Join their guild and chat, meet other people, and socialize. Maybe group with those arathi quests. The open-world experience I find fairly quaint when it's filled with people trying to attain similar goals.
People like vanilla raiding because you're doing it with a bunch of other people. Vanilla raiding tactics are unbelievably simply... mages press frostbolt. Warriors spam sunder. Rogues keep snb up and ss/bs. Paladins buff and spam one heal. These experiences are not terribly exciting on their own--but the social aspect and scale of the raid makes it exciting and fun. Same with vanilla leveling. On it's own, it is certainly boring. Add in a bunch of people in the world, suddenly you get a more dynamic sort of gameplay which allows for grouping, dungeoneering, world pvp, and a sense of progression with others that I feel drives the player forward.
I'm not defending 1x vanilla leveling as super fun. We've all done it before, it's not new. But the socially charged environment of vanilla can make it fun on a certain level.
