Considering that some features announced for previous expansions still aren't implemented, it may be premature to comment on these... but I'm going to anyway.
Level cap 100Nothing unexpected here - it was going to either be 95 or 100, not a huge difference either way.
Updated character models/skinsAlready announced. Personally not too excited here, though some feel this is necessary.
Level 90 UpgradeYou can make one character instantly level 90 and experience the new content right away. This has it's uses for a quick high-level alt, and possibly even a poor man's realm transfer, so I'm not totally unopposed. Sadly, this looks like it will be instantly abused by gold sellers to farm easier than ever before. I'm also guessing that this will become a purchasable service down the road, because people like instant gratification.
GarrisonsBuild your own fortress with tons of bells and whistles. This looks to be Blizzard's answer to the often-requested player housing in WoW. The biggest surprise here is they will exist in the open world. While I vastly prefer the idea of that, I'm unsure of how well it will work in practice. Previous attempts at open world player structures haven't fared well, so it's a gutsy decision by Blizzard. Here's to hoping it works well.
Questing SystemLots of buzz words here like "refined and flexible" with little to explain what that means. Quests can now reward random rare or epic loot, which might be okay. One of my biggest complaints about WoW is that it has a huge world that people can mostly ignore if they choose (get to level 10, set hearth to capital, queue LFD and never look back), and the chance at better rewards for questing may alleviate that.
A "New" WorldThis all takes place on Draenor, which is now known as Outland. Time travel is obviously a major theme of the expansion, and it sounds like someone is attempting to mess with past events (a repeating theme in WoW already). I have mixed feelings here. Seeing the original Draenor sounds pretty cool, but time travel can easily create lore inconsistencies. Speaking of lore, the actual reason as to why this is happening in the past is still unknown. That's intentional so as to generate speculation, which keeps people talking about it.
Not Mentioned in the VideoLevel scaling and number squish. I can see not talking about the impending squish, because while necessary at some point, most players won't like it (mah big nmbrz r gon, wtf blizz). Scaling players/instances to match the other is a great feature used by a number of games, and helps to strengthen player cooperation. They're both coming to WoW at some point, perhaps before this expansion is even released (which may actually be the reason they're not part of the trailer).
Final ThoughtsSome are going to see Draenor and immediately think, "oh boy, a return to TBC! That must mean things are going to be like old times!" only to have their hopes quickly dashed. Face it, that style of play is never coming back to WoW (for better or for worse).
The announced features are a bit of a mixed bag, and I'm sure many are wondering if new races/classes/professions are even going to be added. It's still too early to tell, but I'd think if they were certain on adding any of these it would've been in the announcement. Warlords of Draenor seems more about improving what's already in-game, with garrisons being the major new feature.
That said, I don't see anything that makes me want to return yet. Garrisons would've been nice when more of my friends were playing - it's a great idea for current subscribers, though (which is an important demographic to please).
Perhaps the focus isn't to necessarily bring in new or returning players, but to keep the current ones happy. WoW may be past it's peak, but with millions of active accounts it's still very far from dead. At this point, I think the numbers have pretty much stabilized and Blizzard is left with a strong title that continues to be their major source of revenue. From this standpoint, it only makes sense to add engaging content that keeps those players entertained.