Which is why Doughty has the other safety spot locked down. I'm also unlike most Skins fans, and I can appreciate Doughty. He knows the playbook, knows his limitations and plays within them. When he gets beat, it's not really his fault. The defensive coaches have also always done a pretty good job of masking his limitations and keeping him near the box.
As for Amerson, they need his size at CB, and won't move him. If anything, Doughty gets the start, and gets replaced in many passing situations by Rambo. They've also talked of Hall moving to safety for years, but I don't think they do that this far into things.