Even the area their Purge falls under is, in my opinion, inadequate - as you said, its not exactly endgame location, so players that have their main base here will either be low level or adapted for more modest stuff - even the hardened steel will be more difficult to acquire (either long trips to the north or through passsage with Reaper Queen Boss for required Black Ice), while Star Metal will be luxurious commodity for them. As for thralls, closest are Black Hand, Lemurians, Darfari or Exiles, so not exactly something that could equally compete against tanky and brutally deadly CoS.