As small of a deal as it may seem Center Clock is one of the huge draw when it comes to running a custom rom. It is just one of the many features that can make your device your very own. You don't have to lose your AOSP stock rom just to run this particular mod. You can simply flash a zip file in twrp. This modifies your systemui apk. You will want to be sure to backup your current rom prior to flashing, and you will want to make sure to make a backup. Changing your systemui apk will prohibit you from flashing ota updates. When you are ready to update your device you could just recover your backup. Head to the link below for the download.
via XDA