Holy crap. It's like something out of a dream. Someone pinch me.
Blizzard will be adding Cataclysm Timewalking dungeons, namely Lost City of the Tol'vir, Grim Batol, Vortex Pinnacle, Stonecore, Throne of the Tides, and possibly my favorite dungeon ever, End Time. (I can't say I'm terribly surprised to find that there's no Halls of Origination, the old seven-boss slog.)
In addition, the Burning Crusade event will now include Magister's Terrace, while the Wrath one will include Pit of Saron.
Finally, a new time walking mount, very appropriate for the feature, will be a high-rez, new, armored Infinite Drake mount. Guys, guys, guys, I've wanted an Infinite Dragon mount for so, so long. This thing might become my primary mount. I'm serious.
Valor! Oh god, Valor returns!
For now, it will only be used for item upgrades, like it worked in late Mists. My hope is that this is just because they don't want to itemize a bunch of new gear. But let's talk, serious, Blizzard? Please tell me that Valor is coming back to its full former glory in Legion.
Valor will drop in heroic and mythic dungeons. It looks like Mythics will always drop it, but heroics and raid finder will only drop it the first time each day.
Warforged item upgrades are going to now scale (either with more randomness or according to your gear, I'm not sure.) Baleful pieces in Tanaan Jungle will be able to war forge themselves all the way up to 695, which I guess will save you the 20k apexis crystals to upgrade them - not sure what this means for empowered baleful pieces. Mythic dungeons, along with the valor points, will be able to scale up as far as 725, which is good, and should make farming valor a bit more exciting. If I were Blizzard, I'd raise the baseline rewards here a bit, but oh well.
In the meantime, Mythic dungeons will also have a chance to drop a new heirloom trinket that scales to level 110, preparing the way for Legion.
The Grove Warden mount will not be a store mount, as people had thought, but will instead be a reward from a quest gained by defeating Archimonde on heroic or higher, and then taking some item to Moonglade. It's sad to think I'll probably not get that mount as a result, but if it had been a store mount, I wouldn't have had it either, so... Infinite Dragon mount! Did I mention there's an Infinite Dragon mount?
The Dungeon Patch:
This is all great news, and I'm really eager to see what they have planned to keep dungeons relevant in Legion. I'm also curious to see how the Cataclysm dungeons will be tuned, as they were quite difficult when we were new to them. I honestly didn't expect any cool new stuff during the Warlords cycle. Maybe Blizzard will make up for the lack of major patches with lots of these minor patches.