Full customized and supported watch faces I'd say never.
I would argue that there are a lot of things they could do, between where they are now, and those fully customizable faces that would be vast improvements over the awful looking ones they have now.
There is no reason no to have 3d faces with depth and high resolution looking hands, dials, whatever. Apple could have very cool looking brand loyal looking faces that celebrate apples minimalist design but they don't. All the apple faces look like customized faces created by people that use microsoft paint.