okay , this is gonna sound mega stupid, but are we gonna see the TRUE Sith homeworld? cause it aint korriban, and tython is being shown, so - what about the Sith? Also what about multiple lords? thers the dude in the trailer, is he the emperor?

To my Knowledge, the True Sith as an unrealized plot point were in fact just remnants of Naga Sadows Sith Empire, so we already know the origins and throne worlds of all the various version's of Said Darksiders... Whether or not Bioware will create another sect, or retcon what we already know?
The pre-Dark Jedi Sith are from Ziost and Korriban (Later used as a Necropolis), and I believe that the interbred Dark Lords continued this tradition until the Great Hyperspace war. Later Sith also took their Academies and Capitols back to Korriban too.

Regarding the Emperor, I'm guessing he is Top dog with Dark lords and lesser Sith Rank subordinates, much like the One Sith Order of 140 ABY.

I don't think the Sith in the trailer was the Emperor. I don't even think the Emperor was on Coruscant during its sacking. Wouldn't be a very smart move.

And as aqd said, Korriban, next to Ziost, is the homeworld of the Sith.

This section is reserved for announcements from the SWTOR staff, please direct your Star Wars: The Old Republic discussion to Tython Temple (http://lucasforums.com/forumdisplay.php?f=732) :)

Just to say according to page or video on official site that korraban is the home world off the sith. It says that the original site for both was Tython where jedi all joined there knowledge about the force and created the jedi but there where argument between them some believed the should use the force for there own ends (sith) And other beveled that the should follow the force will (jedi). The jedi cast them out from Tython. The Sith found korraban enslave the local populace and then created there own empire. And then decided that the jedi didn't not deserve to live due to there weakness. That's why the first hyperspace war started.

I think that "True Sith" is nowhere near what they were intended to be in TSL...