There are several gates at the boundaries of Skyrim with invisible walls (i.e. impassable)
One of these gates, I believe is on the Southeast Region of Skyrim, to the east of Riften.
I also notice, that right next to this gate is a tower (I think it's official name is Stendarr's Beacon).

Could one of the DLCs be completely related to the Vigilants of Stendarr?
Amongst my whole experience through the game, I've only witnessed a few scenes, and one quest involving the Vigilants.
There are Vigilants of Stendarr walking around Skyrim hunting Dremora, the Hall of Stendarr is located south of Dawnstar filled with Vigilants, and occasionally the player can see a few Vigilants walking in packs amongst the landscape.

Speculation? Anyone?
I would like a DLC focused on hunting Daedric Lords/worshippers, simply because the game has 16 Daedric centered quests, all of which are fairly lengthy (Some more than others)
I'm not tired of serving Dremora lords, but I'm guessing that Bethesda might want to go the opposite direction with one of the DLCs, simply because the stock game is packed full of Daedric Quests.
There's even an achievement centered on obeying the Dremora!

Thoughts? Opinons?

Probably there for modders.

No. First DLC needs to be attributes and spellcrafting.

I doubt it. Would love to kill more of those self-righteous faux paladins though.

I've only met them on my evil daedra worshipping character, so naturally, i murdered them before they could say "Help! assault!" or if there was more than one, "MURDER!~!~!~!~!"

I hope they get a DLC expanding their lore and gamepay options.

Would really enjoy some Vigilant DLC, time to smite some Daedra!

It seems odd that there's that faction there that you can't really interact with... can't join, no quests for you ect. They don't seem to serve any purpose story wise either (that I've seen so far, I haven't done everything yet).

there's lots of "unused factions" : vigilants of stendarr, forsworn (they are involved in one quest tho), thalmor, vampires, penitus oculatos, alik'r and psyjic order.
eventually some of those might become involved in some DLC.

But all of those factions have some quests surrounding them, through different quest lines (excluding the vampires, although you can become one and such).

There's also the hall f the vigilant, which I believe is near Windhelm. It serves no purpose. I have a feeling you may be right about vigilant DLC!

acgtually I do remember a quest that sends you to speak to the head of the vigilants of stendarr, don't remember if you find him in the hall or not tho.

I can't find it, so could it be a radiant quest like the Hired Muscle in the Companions which gives you a random target?

yeah, maybe, I do remember having a quest mark pointing at the hall once, or maybe it was stendarr's beacon...
the only other thing I can think of involving the vigilants is the "house of horrors"

According to UESP, there's no quests involving the hall or the leader, Keepr Carcette, although I do remember being given a quest about Stendarr's beacon. And I'm sorry, you're right, there is a vigilant in that quest!

anyway they are not much used, pretty much like the psyjic order or the Alik'r, they just show up for one, max two quests

True. I hope there is some DLC of some sort for them, I feel like they don't have any real use.

Also, sorry for my dreadful grammar, I'm on my iPad, haha.

Not gonna happen. You're setting yourself up for disappointment.

I would love this DLC, my assassin needs more people to kill. ^.^