I really hope that Rick and Michonne become a couple in Season 5. I think they have great chemistry and would make an awesome power couple.
They both have strong alpha personalities and I think it could work to their benefit. The fact that they both have dominant personalities, strong wills to survive, and core values gives them a better understanding of each other, in my opinion. They have already developed a deep respect for each other, and both have the desire to keep the group safe. This helps them relate to each other as "devoted friends." I think that's great.