Quote Originally Posted by Watchman
Oh ? What's there to keep them from simply sliding over one another (to a certain degree) as was the standard for laminated armour from the start to the finish ? Not that a hip-lenght cuirass like that needs to be particularly flexible anyway.
Having manufactured a worn something of the like, I can say from experience that the plates restrict your torso movement in very annoying ways. If you look at how a human bends they bend along the the length of the torso. However, even with the flexibility of a curass built like that, it is still fairly restrictive. They slide but not by much.

It does however allow for good all around protection that is form-fitting, not bulky, and easy to make with decent flexibility(turning and bending a little). Its definately better than a giant plate on your chest.

However, like you said, flexibility isn't a particularly large issue. Kevlar armour with ceramic plate doesn't alow the user to bend much either. It hasn't been a huge issue in battle throughout history.