http://elderscrollsonline.com/en/news/post/2013/05/03/ask-us-anything-variety-pack-4
Most of it is boring gameplay stuff, but there were a few points here that stood out to me:
"Something that is in big debate on every single forum I've seen as of late is the life expectancy of the different races of Tamriel for roleplaying purposes. Can you please elaborate and give us some numbers to work with for each race or at least the Elven races (Altmer, Bosmer, and Dunmer)?
Elves live two to three times as long as humans and the “beast-races” (Orcs, Khajiiti, Argonians). A 200-year-old Elf is old; a 300-year-old Elf is very, very old indeed. Anyone older than that has prolonged his or her lifespan through powerful magic."
At the time of Tribunal, Barenziah was 430. I know that The Real Barenziah makes reference to her wielding destruction magic at one point, but was she ever known as a particularly powerful mage, or is the above simply wrong? (Divayth Fyr is another obvious example, being 4000 years old, though if he doesn't qualify as powerful, I dunno who does - and Master Neloth is looking damn good in Dragonborn for being, at the bare minimum, "very, very old indeed".).
"What is the social and legal opinion of slavery in Tamriel during this time period?
It varies by jurisdiction. The Clans of the Reach, for example, certainly keep captured enemies as slaves – but they’re barbarians. In most civilized realms, slavery is illegal, with the obvious exception being Morrowind. Under the terms of the Ebonheart Pact the Dark Elves have had to liberate their Argonian slaves, but they still have slaves of other races, the most common of which are Khajiit."
So that answers the question of what the Argonians get out of the Ebonheart Pact, if they see it as an opportunity to liberate themselves long-term.
"Are we going to encounter Dragonborns in ESO or learn shouts ourselves?
The line of Reman Cyrodiil of the Second Empire was certainly Dragonborn, but they died out at the end of the First Era, and between then and the date of ESO, no “legitimate” Dragonborn has been confirmed by being able to light the Dragonfires in the Imperial City.
As for shouts (i.e., thu’ums), at the time of ESO, they are considered a legend out of the distant past."
This is surprising to me- even though the Tongues were disbanded by Jurgen Windcaller in the early 1st Era, I was under the impression that the Greybeards were still taking students and teaching the Thu'um to them (Ulfric jumps to mind here). I hope they go into greater detail on this point - maybe the Nords simply forgot the Greybeards were up there until Talos came along?