For me, I love being able to change my soldiers to people I know. This was such a small thing in the new XCOM games that added a lot of enjoyment for me. So in addition to just allowing changing our soldiers names, I'd love to be able to change appearance, gender, and nationality on top of the existing name change, to match people I know.
I know this isn't the most pressing thing and I'm not saying this should come before major features, but I still think this is a small thing that would add a lot to the game and should be done at some point.