I don't know the Saga model, so I cannot comment on that.
If you take out multiple attacks, what fundamental change happens in the system? I can see thing's not changing all that much (in the sense of a standard attack) from what we know if attacks are fully replaced by something like the Book of Nine Swords. Which I guess we know is happening.
If they completely remove any chance of rolling a second attack die even if you have two weapons, then it all depends on how they mechanically show that second attack. Do you increase damage? Perhaps you automatically double your damage die result. Or maybe you hit once, and roll both die for each weapon? Or will things be harder to hit in general, and that second weapon will only increase your hit chance?
A whole lot of choices here. Personally, I like the idea of you losing chance to hit and rolling both damage die if you do hit.
Too many possibilites to really know if it would be effective. It seems like they're going to make each weapon special, so I don't see why a single weapon style, two hander, sword and board, or two weapon would be any different.