Depending on which race and faction you go with it can effect the design. For example the Blood Angels have their own iconography over teh Space Wolves and Ultramarines. The same principle applies to their second founding chapters. The second foundings all have distinct traits linking back to their heritage. As for the customization idea. I would imagine they would do something similar to the paint program from Bolter & Chainsword. Where players can adjust the colors of Solid, Halved, Quartered, or Random to the design? That is a guess on my part.
I'm sure you can tweak certain parts of your armor. It wouldn't really fit to change it too much though.
I think they may do a mix, though hopefully I hope they just use the simple RGB colors and not use the shining metallic colors like seen in DOW 2s color pallet. Back then a lot of players splashed Loud, Shiny, metallic colors on their units.
I dunno. I like the idea of having full customization to my armor. From the color of the Aquila, if it's halved, etc. I mean if you check out the various color schemes for existing space marine chapters they have a wide variety of patterns, as well as ranking colors.
