1. It's not new zone for 9.1. It's just addition for Maw with new quest line.
2. You allowed to do quest in first week of 9.1
3. After you complete starting quest line you can use mount in Maw and Korthia. You also not affected by Eye of Jailer.
4. Flying in SL (44 renown) not apply on Maw and Korthia.
5. There's 2 new assault in Maw ( same as N'zoth assault in 8.3). You have to do it because you'll get 50 soul ashes.
6.New ivent and world quest in maw. After you complete ivent you'll get 50 soul ashes once in week. After you complete world quest you'll get reputation only.
7. Weekly in Korthia provide 1 renown and 10 stygia dust - you need it for upgrade domination socket.
8.There's lot of quest in Korthia in the beggining. You have to do it for reputation with 2 new fractions.
9. New world boss in Korthia avaliable since 2nd week. It's drops 233 loot and shard of domination and couple conduits.
1. You need to be honored with Death's Advance as soon as possible for be allowed to buy 220 item with domination socket
2. Reputation with Archivists' Codex similiar to Venari in 9.0. For raid characters it's necessary for sockets/upgrade conduits/ and free 239 item level slot with domination socket.
3.In Korthia you can get 233 gear for your alternative character. This upgrades locked on 61 and 75 renown. During the progress it will be useless.