I heard that the argonians were wiped out in the war with the dark elves and thats why we wont be able to play as them, guess it would have been silly to have a cold blooded race roam the cold north anyway.
Wasn't it the other way round, after the MiniTrue splats Vivec the Argonians get their revenge on, forcing the rest of the Dunmer to migrate to Solstheim, no doubt delighting the local Skaal. Infernal City's canonicity will be put to the test given the timespan, IC being set ~40 years after Oblivion.
All this is academic, however - all 10 races are confirmed playable. Probably will be some established Dunmer refugee strongholds in the east, or something.