There are plenty of directions to go, but I think they cheaped out or at least wanted to keep consistency with the rest of the body for clarity purposes. Maybe even Disney wanted that for an "authentic" feel of each of the battles being recreated (forgot Heroes showing up in places they shouldn't be..). Still crummy, as I'd rather a bit messier looking of a battlefield than shitty customization options.
I think the face customization, if present for Imperials, will be for those that do not wear helmets or wear faceless helmets. I doubt we will see helmetless troopers as based on everything we've seen and heard, Dice is staying true to OT and canon.
Maybe we will see DLC such as AT-ST Driver, Imperial Navy Troopers (seen in Death Star ep IV), Officers, etc.