There's also patch 7.1.5 before that which also has a singificant amount of stuff in it for not being a "full" content patch:
In the past, the team has had large monolithic patches that have anchored the entire expansion.
A patch like Patch 6.2.3 was very effective. The team wasn't trying to add a ton of content, Moose Mount, Valor Points, Timewalking, and other things.
Patch 7.1 is a good example of a medium sized patch.
Patch 7.1.5 is Legion's first small patch, similar to Patch 6.2.3 in size. It will revolve around systems, new rewards, and evergreen content.
Pushing out a smaller patch allows the team to give us some new content faster.
Patches should be designed to be broken apart into multiple pieces, so that if one piece isn't ready, it can be removed and the rest of the content can be released.
Patch 7.1.5 will have Mists of Pandaria Timewalking, with six dungeons.
Timewalking will probably only ever be updated for the expansion before last. No one is excited about going to Warlords dungeons right now.
Patch 7.1.5 will also bring back the Brawler's Guild! It will come back with dozens of new bosses.
There will also be a new type of battle that can occasionally occur, called Rumbles. These spawn raid level bosses that will pull in all players who are waiting for their turn into the arena. Everyone can share in the rewards.
A new currency is being added, earned through your brawls. It is spent on shared benefits, such as a graveyard that lets people respawn at a graveyard next to the fight area.
There will be shirts and a Basilisk mount as rewards.
New micro-holidays are coming. These might last a day or two, rather than a week or more. These are part of building a living word.
Jan 22 - An'Qarj Remembrance Day.
These holidays won't have any pets or mounts that you sad to miss out on the event.
Valentine Guard Day - You can patrol the city and keep it safe from NPCs that attack.
Hatching of the Hippogryphs - You can get a baby hippogryph that can perch on your shoulder, no battle pet or anything.
Boat Day - Like Spring Break for Azeroth.
Patch 7.1.5 will also update Blade's Edge Arena. No gameplay changes, just updated visuals. Arena will have a built in voice announcer, will call out some events.
Patch 7.1.5 will also bring lots of class updates, allowing the team to make larger changes to classes rather than just number tuning.
The team looked at all of the talent rows, there are some talents that are never worth considering. These talents may need tuning or redesign. The talents that 98% of players are taking may just need to be baked into the spec.
This patch will also allow the team to look at secondary stats to make them a little more balanced, so that anything but one specific stat isn't useless. If an item has a higher item level, it should usually be an upgrade rather than having secondary stats make it a downgrade.
The team is also going to try to improve the feel of the classes and add some utility to classes that had a little bit much pruning.
Only allowing Survival Hunters to have traps was a mistake. Other specs don't feel like a Hunter when they don't have traps.
Rogues that wish they had Shroud of Concealment will also be happy to see it return in Patch 7.1.5.
Patch 7.1.5 - Artifact Knowledge catch up mechanisms, purchase levels without waiting up until Level 10 or more.
Patch 7.1.5 is going on the PTR right after BlizzCon.
I think it's safe to say Blizzard has surpassed expectations.
Also where the death knight stuff at?