I have the same issue and it is a serious problem. I missed messages because there is no indicator in the status icon area of the normal screens.
I know I can go in to control center and see the status but I have to remember to do that so it is not a solution.
I know I can schedule Do Not Disturb but that does not fit with my wake and sleep times. I am sometimes up very late and others to bed early. So, this is not a solution.
Apple, please add the half moon icon to the status area of the normal phone screen. Maybe have a settings option for simplifed (like it is on iOS 11.1.2) and a new “full” option that makes use of the high screen resolution to have 2 rows of status info if you cannot fit it on one. Then you can add back the battery % as well.
The way it is now makes the DND feature unusable and this is very disappointing for such an otherwise great phone.