The Android Wear line up does not get as much love as the other devices that Google supports, it does take some time for updates to roll out to devices but recently, a new update has come to the Android Wear devices that will enable a system-wide dark theme.
The new theme will replace the grey theme that is on existent Android Wear devices but it will only come to devices that have an AMOLED display and the others will not get the theme. Currently, only the Huawei Watch 2 and the Huawei Watch has been confirmed to get the theme. It will also bring new and improved features like third-party chat app support in Contacts, reduce accidental entry into watch face picker, improve Play Store discovery, bug fixes and other features.