I think robes and winged helmets are a must have for Dark Angels. They can create different styles of the robes. Opened, closed, with different motives on the chest. And I hope it's possible to customize the weapons too. Like wings, feathers, chapter icons, claws, teeths, blooddrops etc.
Yeah, we need robes. DA without robes? True Heresy. Anyway, a stupid question. Assault marine can wear a robe? At least a hood kind of thing. I will be honest. If the devs will make some unique customization for every chapter, I will pay for it. Why? Because this will be support for the devs.