The weird thing is that you can rotate your character, just not in the customization screen which would be the logical place for it. Rotating your character does work but in the LOADOUT screen, you can also rotate your weapon there. Why this is? I have no clue ...
NWI should fix this, it would be great if it worked in both screens (loadout & customization) and also: please let us ZOOM in/out with the mouse scroll wheel (NWI should look at WW3 to get inspiration how customization can be done in the UE4 engine ... the way they do it is miles ahead of what can be seen in many other games and they are a small dev team as well)