Obliterate and Frost Strike currently 'require' two one-handed weapons to use, so allowing Frost to return to 2h would have to be a conscious design decision on Blizzard's part rather than a measure of player agency. I doubt they will do that for the same reason they took it away: because they don't want to have to balance two versions of the same spec - it's just more balance work.
That said, I prefer the 2h days greatly.
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Yeah that will never ever happen. Don't think I'd want it anyway. Already bothers me you can mog swords into maces, etc