Not exactly a missing piece, but an issue. I created an Arachnos Soldier. With the female model, I loaded up a costume pulled from Sentinel. With this archetype, you've got the "Wolf & Helm" and "Bane / Crab" options, which determine everything else you can get. With the "Wolf & Helm" selected, which is what I had for the costume in Sentinel / CoV, there is no option to remove the crab backpack. It's under the "Back" option. There should definitely be a way to remove that, since my costume as saved did not have the crab backpack. Plus that should really be kept in the Crab options, right?