The idea of the expansion came up after the heroes of Azeroth dealt with so much external threats like the Burning Legion. In their own words, "so when we talk about what's the biggest threat in this world, is it the titan or is it the dwarf paladin that put a hammer in that titan's head"? As such, the enemy (at least during the early parts of the scenario) will be the opposite faction, a "vast army of world-destroying forces".
[Expulsom] is obtained primarily from scrapping armors and weapons using the Scrap-o-Matic 1000 (Alliance), or the Shred-Master Mk1 (Horde). These tools work like disenchanting, you can break down any gear obtained that is from the Battle for Azeroth expansion, including dungeon/raid drops, quest rewards, world drops and crafted gear. The Scrapper isn't restricted to specific trade skills. Anyone, even people without a crafting skill can use it. You will mostly get ores, gems, leathers, cloths, and occasionaly you will get one [Expulsom].
Guild Banners. The Banner of Cooperation and Battle Standard of Coordination will increase the experience from kills. They both have a 10 minute cooldown, but when you use one, the other is only locked out for 2 minutes. I was very bad about using these, so it might be worth using a macro to drop them on your first attack against an enemy. Keep in mind you must have reputation with your guild before being able to buy these, so new character may have a bit of a wait before picking them up.
Professions skills are split between expansions now, you'll have a separate skill bar for each expansion. There are still 950 profession levels in total, just that there is no one single progress bar with 1 to 950 for it anymore. Instead, there are 8 separate progress bars. (The only exception is Archaeology, because it will still have a 1-950 progress bar)
Both guides have a different look. Many players choose the Zygor guide because of the way it looks, with it’s modern, clean appearance. Zygor has improved it, so its easier to navigate. Dugi Guides interface blends into the game more, as it looks more like something you would find within World of Warcraft. It has icons down the right hand side for selecting your guides and is really easy to navigate.
/way commands like /way Shadowmoon Valley:Draenor 50.0 31.2 Ashlei don't work correctly. According to the way TomTom works, this waypoint should be created in Draenor's Shadowmoon Valley. Instead, it will be created in Outland's Shadowmoon Valley. So it seems there is currently no way to distinguish between zones that occur more than once with the same name, such as Shadowmoon Valley or Nagrand.