In my recent Daggerfall replay, I found nothing in the lore suggesting that the Altmer were potential bad guys.
That's because there's only two Altmer in the entire game. http://www.uesp.net/wiki/Daggerfall:Mannimarco
I believe some books in Daggerfall make reference to Altmer being snooty and arrogant and having feelings of superiority.
I can't remember if the Thalmor is referenced in Oblivion.
It's not going to be referenced in Oblivion because the Thalmor weren't around back then. There were 200 years between Oblivion and Skyrim and a lot changed. Before Skyrim, the Thalmor were only called the Aldmeri Dominion, and I don't know if Oblivion has any books that reference it, but I know the Aldmeri Dominion was mentioned as early as Redguard, with the first Pocket Guide to the Empire.
I'm replaying Oblivious now and I haven't seen any reference to Altmer douchebagery. It's entirely possible I haven't scene it yer tho
That's such a perfect typo. Altmer are practically the villains of the entire game. Mankar Camoran and his kids, Mannimarco, Umbacano, Falcar, Earana, the list goes on.