It’s a good thing that the previous expansion, Legion, was the best in the game’s history because Battle for Azeroth is coasting on its success. The major class redesigns that happened then remain in effect (though some are a little worse, and some a little better), and the combination of World Quests and Mythic+ dungeons means there’s always something to do, no matter your skill level or how long you can play.
No. Never. Buying leveling guides is a waste of money. Any type of information covered in Zygor is more or less found all over the internet. Leveling is so fast and streamlined now there shouldn't be a reason to use a guide. Go to the zone recommended for your level and do about 20 quests and you're already on to the next zone, outlands, northrend, and cataclysm content is so fast now you can do all 5 or 10 levels of the expansion in one or two zones.
Warlocks have received new spell effects; all the other classes received new effects in Legion. Male orcs are now able to toggle between the initial hunched posture and standing upright by using a barbershop, but the other races are not able to toggle between two postures. There are new druid forms for the allied races, i.e. a Zandalari troll forms are all dinosaur-based, while the Kul Tiran humans take forms made of wood and bone as their teachings come from the Drust people who populated the land before them rather than the Cenarion Circle.
Tiragarde Sound and Stormsong Valley are both fairly similar zones, but Stormsong is a little longer, meaning that you might not even have to finish it to hit 120. Tiragarde also comes with a bit of a warning. There are plenty of side quests to do in the zone after you finish the story quests. Don’t do them. It’s not worth the time or the experience you’ll get.
Zandalari troll (8.1.5) - "The Zandalari are a proud people whose origins date back to the early days of Azeroth's history. Their fierce warriors ride dinosaurs into battle, and they possess one of the most formidable naval fleets in the known world. But enemy attacks on their borders—as well as unrest within the king's council—have threatened the kingdom's foundations. By returning stability to Zandalar, the heroes of the Horde can gain a powerful new ally.."
Despite the fact that World of Warcraft still relies on the old 14-year-old game engine, the game can cause some frame rate drops even on newer hardware equipment. So we've decided to devote a lot of time and space to answer such questions like: How to set up the graphical options? What should I do to make sure that WoW runs smoothly? WoW's hardware requirements have evolved over the years due to graphical improvements, so find out if your computer can handle the highest graphics settings of the game.