Marksmanship would make RDM/COR viable.
On to daggers, they would have to add us to some actual daggers, because we haven't gotten almost anything but swords post 75. The Aluh Jambiya is slow and -10 VIT, the Gnadgott is unremarkable, the Oneiros Knife is low damage, and the Twilight Knife doesn't work with Enspells. Of the 4 daggers listed, we should only be able to use Gnadgott since it's a dagger or baselard model. We aren't on knives or Jambiya before 75.
Honestly we would be offhanding Mandau and that is terribly expensive unless they wanted to give us the Attack from it.
It seems significantly unlikely that they would make an alternate to Dual Wield only for one job. At least with a Spell that emulated Traits, it seems conceivable, since BLU gets Dual Wield traits by setting spells. Not the same thing, I admit, but Temper isn't much different from the Double Attack Trait. So at least I could see it being possible.
I still doubt we will get Native Dual Wield, so long as we still have Shield Mastery. I would like it, but I don't think we are getting it. Then again the same thing could be said of THF at lvl 75.