We actually considered this approach when developing the component, and our UX decided against it.
Sorry but we won't be accepting this flexibility. One of the goals of these widgets is to keep consistency of Google products where these components are being used. This could break that consistency in our products. Beyond that we limit the amount of flexibility that we allow for performance/maintenance reasons. We allow a lot of flexibility when it can be added with mixins which don't make the performance worse for the product customizing it, but we limit it on the dart side because it makes all the products slower.
We actually considered this approach when developing the component, and our UX decided against it.
Sorry but we won't be accepting this flexibility. One of the goals of these widgets is to keep consistency of Google products where these components are being used. This could break that consistency in our products. Beyond that we limit the amount of flexibility that we allow for performance/maintenance reasons. We allow a lot of flexibility when it can be added with mixins which don't make the performance worse for the product customizing it, but we limit it on the dart side because it makes all the products slower.