This is something I find, given thought, a bit of a oddity on blizzards part when concerning the lore, the races and the introduction of monks into the game.
Now take every race in wow and think about there history, backstory. Things like how orcs lived on draenor and had shamans as spiritual advisors and leaders, and how warlocks came into there culture by the legions influence and gul'dan's manipulation.
Think about how paladins came into being in the alliance first, how they were once priests who became warriors of light to fight against the horde, and then later how blood elves took the power of a narru and turned it into something they use to fight with, or even the tauren who discover another form of druidism in sunwalkers.
Or take the reason why all forsaken and there classes lorewise will also have a sinister edge to it, like shadow priests and warlocks, and how the they can't be paladins because of the holy light burning them up.
And then.. take monks. This is where the lore takes an unusual direction. With no cultural reason and no background other then what the pandaren did, all races (except worgen and goblins for some silly reason) suddenly just adopt monk-hood like its always been part of there culture, with no real story to back it up, and thats just acceptable?
Even deathknights have a proper reason why all could be them, whatever someone was before becomes meaningless when Arthas raised them as undead warriors.
Perhaps I find it, slightly gimmicky when all it has to back it, is a travelling pandaren showing up in starting zones saying 'hey, you want to be a monk?'. Its even more weird when a pandaren just happened to be wandering around an uncharted island on his own when he see's the exodar crash there and then invites drarenei to learn his ways.
Pandaren are the only ones who make sense in this, since starting on the wandering isle there culture is based upon monk teachings.