Well, there's no arguing that if you want to stick to one disk you can have a much bigger one disk BR title than DVD, but this smells more like a DLC money grab to me with the usual pre-release posturing.
I remember the good old days on PC, you got the full game and maybe found some remains of cut stuff in the SDK. Sometimes the developer would release it for free as a 'thank you' and bit of fun for the fans.
Now we get to pay for it as DLC. Great. Or have material better suited to an expansion pack justified as a new release at full price.
My, I'm feeling bitter today.
My view is, if they're telling the truth then either use multiple disks on 360 and one BR and release the game you want or stick with your decisions and commit to a game that fits on 1 DVD.
Bloody moaners. Like me.
Try to be reasonable... its easier than you think...