The Worgen have gotten a bum deal, both in-universe and in a meta-narrative sense. In-universe, Gilneas was invaded by the Forsaken and a good portion of it sank beneath the sea during the Cataclysm. And that's on top of the civil war that began after the building of the Greymane Wall and the spread of the Worgen curse (something I only found out recently was part of a Forsaken plot - Sylvanas made a deal with Ralaar Fangfire, aka "Alpha Prime," the Night Elf druid who was the leader of the Druids of the Pack.)
In terms of the meta-narrative, the Worgen were introduced in Cataclysm, but their role was pretty much negligible. While the Goblins played a huge part in helping to modernize and mechanize the Horde war machine, which led to the escalation of the conflict (and eventually the creation of the Iron Horde,) the Worgen didn't really change the character of the Alliance at all. There were a handful of questing areas in the Cataclysm-ized old world, but they had practically zero presence in the 80-85 zones (there were a couple Worgen around the Shrine to Goldrinn in Hyjal, but the good ones weren't even in their Worgen forms.) Since then, there hasn't been any real Worgen story - Genn Greymane sits in Stormwind (in human form) and we hear vague talk of "going back to Gilneas" but never any action.
There's cause for hope, though I would take it with a grain of salt. Genn Greymane is listed as a primary character in Legion on its website. That is potentially very exciting, but don't break out the GIlnean Brandy just yet.
Literally just having Genn do anything is something of a relief for those of us who like the Worgen, but I worry that Genn is being set up purely as the Alliance counterpart to Sylvanas. We know that Sylvanas is trying to uncover the mysteries of the Val'kyr to avoid her own death and damnation (she's rather justifiably convinced that if she does die, she'll find herself in the Void, not whatever place good elves go when they die.)
I'm happy to see Sylvanas gettings stuff to do (I'm a big fan of the Forsaken as well,) but the thing I worry about is that Blizzard has a tendency to have the Horde act and the Alliance react. Sylvanas is being proactive - going out there, trying to find a way to save herself. It would be a real shame if Genn's story was simply to try to stop Sylvanas. We could, very easily, essentially have the same series of quests, with a "get there first" motivation. The problem is that this basically defines Genn by Sylvanas, and it defines the Worgen by the Forsaken.
There's a lot more to the Worgen than simply getting revenge on Sylvanas.
I'm certain Genn's going to be aware that Sylvanas is there, and he's not going to just leave her alone, but I think there's a golden opportunity to get into the nature of the Worgen curse. Why, for instance, is it infectious? The idea that the Druids of the Pack couldn't control the ferocity of Goldrinn makes sense - they'd become feral beasts who can't tell friend from foe. But when a wolf bites you, you don't become a wolf.
We know we're going to be dealing with the Emerald Nightmare. I think it would be really interesting if we found out that the Worgen curse actually comes from the Nightmare.
See, part of the problem I have with the way the Worgen have been explained is that it's kind of... benign? Clearly not benign exactly, as the Worgen are, without that ritual to restore their control, vicious violent creatures. But ultimately, it's all based on Druidic magic that is totally natural and derived from a revered Ancient.
It's not really a curse. It's a blessing that was calibrated wrong.
I want the Worgen to be the product of dark magic. Yes, they're good people, but let's make it a real curse. Plenty of playable races have dark origins. The Forsaken are undead, the Orcs and Blood Elves are marked by Fel magic, and the Goblins got smart by drinking something that might be Old God blood. The promise of the Worgen was to give the Alliance a dark and monstrous race, but beyond the rainy grey/brown/black aesthetics of Gilneas (which I love, mind you,) they're not really any "darker" than humans or Night Elves. The biggest problem of the Curse is dealt with in the quests in Gilneas.
It would be really cool if we could uncover that the Druids of the Pack were either being corrupted by the Emerald Nightmare, or even better, using the Emerald Nightmare's power to make their form infectious in a kind of misguided attempt to force it on the rest of their society. It would be great to give the Worgen a conflict that didn't rely on the Horde doing something awful to instigate it.
I worry, though. Maraad and Velen were both listed as important figures on the Warlords website, and both died before you even made it halfway through the leveling experience (ok, Maraad died at the halfway mark.) I could totally imagine Genn basically playing the role Matthias Shaw did in Twilight Highlands - being the half-assed Alliance counterpart to a more interesting Horde character and plot.
Also, with Gilneas sitting as a totally empty zone (except for a few Mastiffs to tame in the north) once you're done with the quests there, it seems like a really easy thing to use the zone for high-level content. Questing through the zone on a Mage the last couple days (and seriously considering race-changing my level 100 mage to Worgen so that I'll have a Worgen character I know I'll play and since I already have another Draenei I play often,) I was struck by just how cool it was fighting through Gilneas City. The original concept for the Gilneas battleground was that it was going to be urban combat, but they decided that line of sight issues would penalize ranged classes too much. But I'd love to have excuses to fight on the streets of GC.
Anyway, with Legion being the fanservice expansion, I think a truly expanded role for the Worgen would be a welcome part of the package.
And hey, how about a model update to Worgen and Goblins so that they can make actual facial expressions?