Hmm... I have my doubts...
If you look at the new Unchained video:
At around 03:00 and some seconds on (during the interview with Jason de Heras - Combat Designer), you can clearly see in the monitor design silhouettes for swords.
On the left you can see what looks like single edged swords. Some even have hand protection on the handle.
Then, there´s a vertical line dividing the swords and on the right the designs change to double edged swords, which are the ones we used in the beta.
I think we may have something here.
He also talks about Shields as secondary weapons for Kratos in single player. I really doubt they have you use a shield in one hand and a BoC blade on the other one.
I really think one handed swords are in.