The problem is it would be very tough to implement. In Fable II, the Sims-like "I love you" animations your character went through fit well with the humour (and, frankly, quality) of the game. TES doesn't exactly work that way.
The other popular romance option in modern games is the Dragon Age one, which only worked because the love interests were with you for the entire game and there are only two or three. Again, it doesn't really fit well with TES' open-world, do-whatever-you-want structure.
So it would either fall on a mini-game like the speech wheel (dear lord, please no) or some unrealistic dialogue choices ala Dragon Age.
If they can find a way to make romance realistic and immersive and not downright funny, more power to them. I still won't use the system. I use video games to ESCAPE things like relationships
EDIT: What are you talking about, SupahDonkeh? Fable III's been out for, like, months. My little brother bought it on opening day.