Raids
Raids will open roughly two and a half weeks after the expansion releases. This will give players time to level and enjoy some dungeons and other content before they move on to raiding.
Normal and Heroic will open first, with Mythic and LFR starting to open the following week.
Blackrock Foundry will open some number of weeks later. (4 weeks for MSV before HoF opened was too short - WatcherDev)
Grommash is really the final boss! When players get to the Grommash fight, they will see that it is a completely different fight from the Garrosh fight in Siege of Orgrimmar.
There will be more than just Orcs in the raids. For example, there will be a heavy Legion influence in the raid that has Grommash Hellscream.
Items
The other legendary items will most likely come from defeating really difficult content.
Warlords will have more activated trinkets compared to Mists of Pandaria.
Challenge modes will reward players with transmog weapons for Gold, a mount for Silver, and a title for Bronze. (WatcherDev)
Challenge modes will have a daily quest that can reward Raid Finder quality loot. This will give players a reason to do Challenge modes while they wait for raids to open. (WatcherDev)
Garrisons
Depending on what buildings your Garrison has, there will be different relevant content out in the world.
If you build the Inn, you will have a dungeon daily quest in the Inn, similar to the Wrath of the Lich King dungeon daily quests.
There are four tiers of Garrison missions for your followers, giving followers increased item levels and access to better missions each tier. Eventually you will have access to a mission that rewards raid quality loot every couple of weeks.
Misc
Armistice Day is on the Tuesday of the release week, which is why they went with Thursday instead of Tuesday for release this time.
The team has talked about doing an updated version of Karazhan, but it was created as a 10 player raid. There isn't space for 30 players.
