OK, FORGET ALL OF THIS MALARKY.
The expansion/DLC NEEDS TO BE:
THe Elder Scrolls: NEW VEGAS.
You can arrive in town on foot - maybe on a quest to deliver a message to an exiled jarl who'se taken refuge there. Like.....a Courier.
There will be hordes of cash in the casinos, lots of different races, maybe even a brothel with custom dwemer automatons (which, if you decide to 'interact' with, run the risk of making you blind.......)
The airport could consist of dragons taking off and landing - finally the dragons will have found a safe place to be and actually have an opportunity to ply a trade and earn some cash, instead of landing in towns and villages and breathing fire/frost on people.......also the dragon mount comes in here, of course.....
All the billboards, elevators, escalators and ground vehicles will have to be of dwemer construction.............
And the main quest could revolve around a military stalemate between the Empire and the Thalmor who are fighting over a source of great power, which just so happens to be in a dwemer structure that is..............A Giant Dam! Yah, that's it!
Am I onto something? Whaddaya think?
Where can the falmor, snow elves, and everyone else be brought in?
And YES, it can have vampires and werethings.........even werescorpions.........in fact, there can be super huge giants infected with vampire disease, that locals call...........Deathclaws! Wow, what a great idea!
Feel free to add suggestions. This could be the Mod of the Millenium - something like Desert Storm mod was for BF 1942.
