I never got the whole "It's a fantasy" argument -- yet Lord of the Rings is clearly fantasy yet it still had a realistic aspect to it -- There's fantasy of all kinds, it doesn't have to be a crayon factory game like WoW is to be a fantasy, even Ul'dah's opening shows that nothing is flawless.

Thus why a class dedicated to monster taming (aka training) would cement that idea even better than random adventurer a walking up to a monster and taming it out of the blue, since as someone said "in a world of vast technology and magic", you'd think there would be practitioners in monster training that can teach you (aka class/job unlocking) to do as such.