Since it is a new expansion pack, there will certainly be new game mechanics.
Here is a summary of the expansion pack:
Opening a new adventure map—Broken Isles.
In The Endless Sea, scattered islands that were once part of the Ancient Continent are fragmented due to a great explosion, now serving as a base and springboard for the Burning Legion to invade Azeroth.
The area is teeming with frightening monsters, filled with fortresses and barracks built by the Burning Legion. Any Adventurer who comes here will fall victim to attacks and slaughter by the Demons.
A new Legion-level dungeon has been opened—Temple of Sargeras.
This ancient temple, submerged for thousands of years, reveals its secrets once again with the awakening of the Demon Lords.
Even though Sargeras's corpse has been removed to construct portals, countless secrets and treasures still remain in the temple, luring Adventurers like moths to a flame.
