More stressful? Maybe. Definitely more monotonous, so a valid point.
Less productive? Hardly. Install a Gold/XP tracker and see what your rates are clearing a bunch of quests, vs cleave farming your way through Cathedral/ZF comparatively in the same time.
You make stupid amounts of money and XP doing this–if you didn’t, people wouldn’t be doing it, and we’d all still be out there killing each other over who gets Hogger’s head this time around.