Kakashi cannot have Obito's sharingan anymore because their time apart is over, and Kakashi no longer needs to witness the world for him. Obito is changed and complete and has been redeemed. Now that Obito has both MS eyes we are all (Or at least just me...) hoping to see his Susanoo, not as some super power to win a fight and defeat everything or whatever, but as a totally rad expression of Obito's completeness and his triumph over hatred.
I think a bright white Susanoo would look BOSS. Sorta like the giant energy deity fist attack of Asuma's buddy Chiriku. A susanoo born from the most tender of loves should be bright and joyful and would show Obito's purpose in the right light.
However, I really imagine that I won't care how it will look. If it does happen I will probs puke from excitement, even if it is neon pink or polka dotted...