I'm sorry that the slave races that outnumbered the Ayleids like 10:1 had to cheat by getting help from a god, demi-god and Skyrim to defeat the Ayleids. Akatosh cutting off the endless source of undead and daedra from Oblivion kind've hurt the Ayleids not to mention that the Shezzarine with all the weapons and armor of the 8 divines killed many Ayleid Sorcerer-kings before he was finally killed by the Ayleids. So pretty much, the slave races used cheat codes to call gods to their side to block off their main forces from Oblivion and being outnumbered 1000:1 isn't very good odds, but the Ayleids fought to the end. Even after they lost, there were plenty of Ayleids and they kept in rule for centuries until they were finally ran out of Cyrodiil. *shakes fist at Akatosh* He screwed us!!!
So, the slave races that were outnumbered by the infinite hordes of summoned Daedra something like 10:1 had to "cheat" to change the odds to the other way around? Since when is preventing yourself from being massively outnumbered considered "cheating"?
As for the armor, what's to stop Bethesda from having Light, Medium, and Heavy "elven" armor? The Altmer still make armor, and it was mentioned in Morrowind about various armors of Summerset Isle (Glass) and Orc manufacture, so there's no need for it to be Ayleid. Of course, it could be, but I'd be very annoyed at having ancient relics floating around in consumer quantities again, the way that bandits with Daedric or Glass armor were in OB. The likelihood of the Bosmer creating something that "unnatural" is somewhere between low and non-existent. The Falmer wouldn't be considered "legendary" if their armor was in common use, they'd be a "known" ancient but extinct (or near-extinct) race, like the Dwemer. It's not very "Orc" looking, and doesn't match any of the bulky "semi-techno" equipment we've seen from the Dwemer. That leaves the Altmer and Dunmer. Unless it's a new Bonemold design out of Morrowind (which I'd highly doubt), I'd have to put my bets on it either being "Glass" or some new Altmer type we haven't yet seen.