I think Face ID is one of the best advancements ever. That said, both it and Touch ID have shortcomings on their own. Masks and some shade cause issues with Face ID. Excessively dry or wet fingers can cause issues with Touch ID. Face ID plus embedded Touch ID in the screen would work amazing IMO, even more so if Face ID could recognize a subtle facial gesture, such as moving your head slightly upward after unlocking, to automatically 'swipe up' to immediately access the home screen.
The notch has never bothered me given it enables a functional feature that expedites the speed in which I work. That said, Face ID could likely recognize certain facial movements to execute certain commands and I think this could take the tech to another level in that it would automate certain things without having to physically tap. If I can get super giddy, if Face ID could automatically scroll on webpages based on facial movements, now that would be a crazy awesome advancement.