Legion is only a little over a week away, but one of its biggest features - the Demon Hunter hero class - is already available to play. I know that I've been taking my DH around on several demon invasions, I've tanked a few dungeons on him (and DPS'd one,) and I've been taking him through old dungeons and raids as I hunt for transmog pieces (I've actually been able to solo the first two bosses of Throne of Thunder as Vengeance, the first one on 25-player mode.)
We don't really have the entire Demon Hunter arsenal yet - while other classes have their full complement of talents and will only have to worry about their artifact weapons when it comes to progressing through the Broken Isles, Demon Hunters are going to keep unlocking new talents every two levels until level 110. This does mean that they are at a slight disadvantage for now, but it's not a terribly large one. Still, it will be interesting to see how talent builds turn out once we have access to the whole range. Personally I'm really enjoying my Momentum/Prepared "build," though the cooldown on Fel Rush becomes more of an issue when doing heroics and things are dying very quickly.
The Demon Hunter starting experience is quite good - I need to go back and do it on a different character now that I have access to my far newer and more powerful desktop computer, so that I can really search Mardum for all the hidden treasures. It's also pretty cool to get an early look at the Vault of the Wardens dungeon, which is pretty huge.
In some ways, the level of uniqueness that Demon Hunters get makes me almost wish that they had been able to do similar things for Death Knights - like totally new voice acting and additional character customization features. That said, if they had done all that unique model stuff beyond simple additional face and skins, we probably would have been far more limited in race choices for Death Knights - I could imagine them limiting it to Humans, Dwarfs, Undead, and Blood Elves, which would have left my Draenei out in the cold as it were.
Of course, Demon Hunters are only so unique because of the lessons Blizzard learned making the Death Knight and the Monk.
Gameplay-wise, Demon Hunter do seem to embody the new design philosophy - a very simple core rotation, but with lots of things you can add into it with talents. Havoc, for example, before you take talents into account, is basically Demon Bite and Chaos Strike, with Eye Beam on a fairly long cooldown (theorycrafting even suggests that on single targets, Eye Beam isn't even worth it, though I think Blizzard will either buff that or nerf Chaos Strike a bit to make it more attractive.) But with talents you can make Vengeful Retreat, Fel Rush, Throw Glaive, Blade Dance for single targets, and even Chaos Nova a significant part of your rotation.
On the other hand, Vengeance is not so simple - you have a pretty complex set of utility cooldowns and things like Sigil of Flame and Fiery Brand that you've got to work in in the right way. I'm given to understand that they've been a little weak on the beta, but I'd bet this is just a tuning thing (and of course, a lack of experience for those playing the class.)
Demon Hunters have had a strong debut, and there's an interesting story behind them. I'm eager to see the emergence of interesting Demon Hunter characters - there's no obvious Thassarian/Koltira pairing yet.
I'm also eager to see the look of the demon hunter evolve over time - getting our artifacts with all their different appearances will be a big step forward (right now there are only three warglaive models one has access to for transmog) but I'm also really curious to see how the tier sets evolve.