Unlinking your characters before combat starts should prevent them from moving to stay in formation.
Yet that presents its own range of problems.
Heroes of Might & Magic handled it well with the "Tactics" skill allowing you place your troops into formation immediately before the beginning of combat, but this wouldn't work for D:OS where adventuring and battling all occurs in the same environment. I can't think of a good solution.
I also like the auto-collect suggestion, but that could take some work. We would need to be able to specify what to auto-collect.
The UI for looting with a controller makes looting extremely easy. I don't think it needs to be made any easier than that.
