The Jailer is talking about unmaking reality or whatever, and part of me wants Blizzard to just go totally “WTF territory”, and actually have reality shattered in such a way that several big bads — and good guys — return to fight.
Garrosh is one such character, who was an asshole, but whose sense of honor could lead to him defending Azeroth against the void lords. Meanwhile, perhaps Ner’zhul seeks to aid us, but perhaps having grown some small amount of respect or guilt about Arthas, hopes to see him freed of the Jailer’s influence. Maybe Uther returns to life, but struggles to understand the need to work together with the Forsaken. Maybe the former dead possess Ethereal bodies, allowing them to fight alongside us, but only for a short time?
I dunno. Shadowlands feels like it has been slow going and really pulling its punches.