New Star Wars QA for 1.2 reveals new species for both factions.

[Rawt]

It's not new races, it's new existing race/class combos. They answered this during the sept beta.

[Slowpoke is a Gamer]

There were Miraluka Sith Lords before. Well, "Sith" lords.
http://starwars.wikia.com/wiki/Jerec

Yeah. I read that, but there are none in ToR.

Honestly I think the reason is they had to balance the Pureblood Sith with something. And Miraluka came easiest at the time. But I hope they at least will, through legacy, let Pureblood play Jedi and Miraluka play Sith.

---------- Post added 2012-02-11 at 01:52 PM ----------

My guess is that the Empire will get Miralukas and Republic will get Rattakis. I don't think Pure Blood or Chiss make any sense for the republic.

My Predictions:

Empire
Miraluka > Sith Warriors and Inquisitors
Twilek > Agents and Bounty Hunters.
Chiss > Sith Warriors

Republic:

Rattaki > Trooper, Smuggler, and Consular
Twilek > Trooper
Cyborg > Knights

That would give each class 6 racial options.

Would be a sensible first step.