The experience curve is adjusted to make it faster than ever to prepare for the newest challenges, and each level along the way will provide more meaningful increases in progress and power. All expansion zones are getting more flexible, too; they'll be able* to scale to you and your friends while you level to 50, so it's easy to try a zone you've never played.
Claim a covenant's power: players will be called upon to forge a bond with one of four covenants that rule Shadowlands' new zones, setting the tone for their journey through the expansion with a full covenant campaign. As they level up, they'll get new abilities based on their choice, including class-specific abilities for each Covenant—as well as developing soulbinds with specific covenant members, which grant them access to that character's specific traits and bonuses.
Shadowy Tormentors inhabit this dimension, and emerge from it to torment death knights such as Koltira Deathweaver. The Lich King originally kept them at bay, but after the Knights of the Ebon Blade left his service, the tormentors are now loose upon them. He even appears in the World of the Dead, as he calls it, riding a frost wyrm during  The Power to Destroy.
As you climb the tower, you may discover a floor that contains a Legendary chest. Inside you’ll discover reagents to craft legendary items that can be taken to a mysterious rune sage who will help you build legendary items. You are in full control—you can choose which type of equipment you’ll make and what powers will go in them to make them truly your own.
One thing that has always been remarkable to me in World of Warcraft is how it brings players together from all sides of life to meet with common goals. I've been playing the game for fifteen years, and have played with gamers with all sorts of accessibility needs. I distinctly remember raiding Serpentshrine Cavern back in the day with an amputee friend Paladin who healed an entire raid of 25-players using a mouse equipped with dozens of buttons. He also competed at a high level in World of Warcraft Arena, as well as any able-bodied player I've seen.
World of Warcraft's next big expansion is Shadowlands, set in the realms of the afterlife. The Horde and the Alliance will set aside their faction war to chase a new evil, known only as The Jailor, who has usurped the natural order of life and death. The game is currently in closed Alpha testing, and seems truly awesome thus far (a preview on that is coming soon).
For the first time since the release of World of Warcraft in 2004, Shadowlands will involve a level reduction ("level squish"), with player characters at level 120 (the level cap in Battle for Azeroth) reduced to level 50, with level 60 being the new level cap (as it had been in the original game). In what Blizzard has called a "New Game+ experience", newly-created characters will have an updated starting experience on an island called "Exile's Reach", which will introduce them to the game and its systems. For players new to World of Warcraft, characters who finish the starting experience on Exile's Reach will proceed to Battle for Azeroth content, while veteran players who create new characters can choose the expansion experience they wish to play through to level 50, at which point they would proceed to the Shadowlands.
Adventurers entering the Shadowlands will find the realm of the dead in disarray. In the natural order of things, souls are sorted and sent on to an afterlife realm appropriate to the lives they lived, but starting around the time of the Burning Legion's third invasion of Azeroth, all souls who have perished—including the innocents slain at Teldrassil—are being funneled directly into the Maw. The Shadowlands are starving for anima even as the Maw continues to grow from the glut of fresh souls. Sylvanas Windrunner has been seemingly perpetrating acts to bring about great amounts of death and destruction. In partnership with the Jailer, they have been working toward a common end for some time.