You don’t realize how important reputation is in Wrath and the only way to get some of the reps is to run dungeons. No LFD is fine if you rush and get your reps done as soon as possible, but if you are a slow leveler or playing an alt after you’ve got your main set it won’t be enjoyable since you’ll have to do what we do now, watch and spam the LFG channel until you get a group, which can be 30 minutes, an hour or two hours. Leveling, gearing and getting reputations on your main will take a few weeks, but doing it on your second alt will take months most of which will be standing some place watching and spamming the LFG channel looking for a group.
That’s not a good reason not to have it. We didn’t have fire for centuries either, but the world is much better with it.