World of Warcraft Vengeance of the Damned
New features:
Reworked mount system, leveling system for mounts (both ground/flying);
New passive skills system based on old talent trees (instead of artifact weapon traits);
New in game game similar to Battle Pets;
"Subraces" idea converted in "Dragon Age origins like" system;
World PvP ranking system (Defend and Conquest);
New Order Hall idea with change - each player is follower and they vote for their leaders (who players also). This system will expand class rivalry like Paladins vs Death Knights in Legion;
Plot:
Wrathion using Vision of Time to reveal Jaina vision about her father. Determined she ventures into Shadowlands in search of Daelin's soul. Group of high elves assisting her using void magic for ritual. She makes mistake - Daelin come backs not as she expected and her followers suffers fate worse than death. Kul Tiras in danger.
Main characters of side story are veterans of Second War like Genn, Alleria, Sylvanas, Faol, Danath etc. Old grudges will be used for faction conflict, but at the same time both factions will suffer civil wars.
Jaina will be narrator of expansion cinematic. Daelin's appearance confirmed at the end of it.