still drop, you do not have to be level 110, do not have to have world quest, do not have to be invited to group, area does not have to be flagged for world quests
felguard legionnaires and wrathguard servitors drop the sword, usually not up at the same time. they cycle with 2 other mobs, core dogs, and felsworn. when they are all killed different mobs replace them. friend told me if i see fel dogs or felsworn at the 2 gate areas.....use LFG and server surf, either that or try another time. if you have a 110 you can wipe all the core dogs and then fesworn to get the cycle back to mobs that drop sword
any level can farm them, just have to out run them, you can kite them to guards up the hill at flight path area, with minor speed to boots and gift enchant to cloak no problem. saw a level 20 druid doing it in bear form, they have taunt and can use moon fire in bear form
one trick i found is if felguard legionnaires and wrathguard servitors are up, leave 2-3 alone, and the same mobs type will spawn replacements.