It’s widely known that the top contender for the next expansion is the Dragon Isles, but what we don’t know is how we get there and why. We have little to go off of for what happens at the end of the current raid, but we do know that Zovaal is trying to suck out all the azerite and that we defeat him. While we probably do save Azeroth, it’s possible that Azeroth gets significantly damaged. Two groups of creatures that have been ordered to protect Azeroth are dragons and titan keepers, with Ysera and Odyn having minor roles in Shadowlands. If you know Odyn’s lore, you know he has no love of dragons.
Should Azeroth be badly damaged, Odyn might put blame on the dragons for not doing enough and seek retribution against them. All of the dragons plot threads have been tied up except for one, which is that of the Infinite Dragonflight. The Infinite Dragons are a product of the Old Gods, and if you remember the End Time dungeon then you’ll remember that Baine, Jaina, Sylvanas and Tyrande are bosses in that, all of which have been prominent characters in Shadowlands. These are characters who might be central to the next expansion again. If they are, it’s possible that Tyrande’s judgment of Sylvanas will be for her to help fix Azeroth due to her involvement with the Jailer.
If you remember the Timeless Isle, you’ll know that one of the last quests involving Kairoz shows the death of Soridormi, with the implication being that grief over the death of Nozdormu’s mate is what causes him to become Murozond. To connect this all together, a theory I have is that Odyn will be the villain of the next expansion due to starting a war with the dragons and he will kill Soridormi, causing the Infinite Dragonflight to come into existence. After whatever happens in the pre-patch, Odyn will go to the Dragon Isles and we will follow him there. Thus, we will fight the Infinite Dragonflight there along with Odyn and his forces. But who will help Odyn?
There has recently been a theory that Valor is a type of Light magic in the same way that Domination is a type of Death magic. With the Light being considered a future antagonistic force, it is possible that a Light crusade arrives on Azeroth and Odyn sees them as a way to restore Azeroth. To take over Azeroth, they will have to get rid of the dragons. But with Blizzard taking the story into a “new chapter”, they might want to get rid of a lot of characters to replace with new ones, and to do this they would use Light affiliated characters to be villain fodder. So it would be Baine, Jaina, Tyrande and Sylvanas versus a quantity of other lore characters.
This Light crusade could be the “true End Time” that Murozond saw. Maybe perhaps as a twist, we end up helping the Infinite Dragonflight against the Hand of Valor. This would be a cosmic expansion without focusing on the Light realm in the same way as Legion. I feel that since Blizzard hasn’t given any official hints to the next expansion yet that it probably has a major theme that’s already established which will be used with huge ramifications.