I've decided to go do each of the demonic invasion areas on my Demon Hunter first - a lot of my characters can use the gear, but I figure getting some practice on him isn't such a terrible notion, and also the idea that he'd be leading the charge in the fight against the Legion is pretty in-character (though my Death Knight, who has been fighting the Legion for 25,000 years, not to mention my Paladin, who kind of puts "fights evil" in his the "special skills" part of his resume - and is my main - are going to be hitting these up a lot as well.)
The invasions are not coming in as frequently as they will when we get closer to the expansion's proper launch (though I love that events like the Broken Shore and the unlocking of Demon Hunters have given Legion a kind of soft-opening. I approve, Blizzard!) But so far Illidari Veranos has defended Westfall, Dun Morogh, Hillsbrad, and Azshara. I've parked him in Northern Barrens to await the next invasion (it's also pretty centrally located for the other two invasion zones in Kalimdor.)
I managed to get a little too close to Crossroads when visiting the Illidari camp and got flagged for PvP (I like to think that he's still figuring out which races are Alliance and which are Horde - he'd gone to Outland before the Night Elves officially joined the Alliance.)
There's a new item that can be purchased for Nethershards that wasn't on the PTR, which is a new item level 700 Warglaive (I want to say it's called Blade of the Fallen.) Unfortunately, this is practically just the same model as the glaives you start off with, only without the glowy green effect. You do lose those glaives after Maiev captures you, but you retain the appearance for Transmog, and I've actually got those now (I like the big curved look more than the serrated thin ones you Maiev gives you when she frees you from your prison.)
This glaive is higher item level than the ones you finish the starting experience with, but the quest rewards (actually, cutscene rewards) also have a set bonus that increases your attack power when fighting demons by 500, so the 10 item levels might not actually be enough to compensate, given that from now until you get your artifacts, you're probably just going to be fighting demons, demons, and more demons.
I went with the Fel Bat pet first, but I imagine I'll put together a fairly complete equipment set. I've already gotten almost all of the leather armor pieces from the invasions (plus an axe that has the same item level and also lack of set bonus as the purchasable glaive.) Right now my Demon Hunter is wearing chest armor that covers up his sweet tatts, which probably means I'll need to go transmog that away.
It does look like there's another glaive model that can be unlocked for transmog once the expansion starts and we can get our actual class hall, but I think their focus has been more on artifact variations. I just hope that when the next expansion comes out we keep getting new warglaives, because I really feel like having a Demon Hunter use axes or swords (other than Wargliaves of Azzinoth of course) would just be wrong.