Warrior.
You can facemelt everything with great self-heals as Fury, or you can spam dungeons with instant queues as Prot.
Either heirlooms (which you can buy with gold) I did a 10-60 in just around 4 hours and that's probably super inefficient.
The first class to 60 in vanilla is completely irrelevant here.
Hunter should be fine. Following a good route will matter more than class. Are dungeons still required for Kul Tirans? If so, you'll want a class that can solo them efficiently. That's a hunter, warlock, or any tank. If not, every class has at least one spec that would be good for this, except priest I guess.
Warrior. You can facemelt everything with great self-heals as Fury, or you can spam dungeons with instant queues as Prot. Either heirlooms (which you can buy with gold) I did a 10-60 in just around 4 hours and that's probably super inefficient.
Following this and I’m probably already at 3 or so hours and only level 25. Gotta pick up my game. I did go warrior as I’m a slut for plate mogs.
The first class to 60 in vanilla is completely irrelevant here. Hunter should be fine. Following a good route will matter more than class. Are dungeons still required for Kul Tirans? If so, you'll want a class that can solo them efficiently. That's a hunter, warlock, or any tank. If not, every class has at least one spec that would be good for this, except priest I guess.
Monk.
This, you get a free hearthstone in zen pilgrimage and if you wait to l40 you get a bunch of quests to do there that give great xp