Excellent topic since prior to Mistlands the "Horde is attacking" was seen as an unfair event since it exposed Meadows bases to goblin mobs even before the player had been to the Plains. Possibly one difference here is that if the player had done the usual precautions and had built their Meadows base on raised terrain surrounded by a moat and with stone then the goblins would just run around (except for those fireballs from the shaman) and the player could enjoy a cup of tea and simply wait it out. And most of us learned to construct such bases due to "Ground is shaking" which, while a shock, was not our first exposure to Trolls. So if there was one tweak I might suggest to our developers it might be to structure this new event more like the "Ground is shaking" or "You stirred the cauldron" where you do have to kill one of these creatures in order to trigger the event. Then fair is fair. You kill us, we attack you.