Bending the wrist back that far on a human causes the skin to bunch and wrinkle.  A mesh won't do that without a morph specifically designed for that type of extreme bend, because the mesh is a hollow shell, not layers of flesh and bone.  If anything is wrong with Dawn's wrists, it can be adjusted simply with weight mapping, so that it bulges slightly instead of indents.  It's a rigging issue, not a modeling issue, and it's certainly not the first rigging issue we've experienced in Poser/DS.  Over all, I applaud Dawn's rigging.  It's better than any I've seen thus far.

 

And for users, use a magnet if you're to make those sort of extreme bends.