So the idea is to define a component in a general language for great configurability, and then make it possible to consume / instantiate it with YAML.

What if the way you wrote the component does not allow some sort of dynamic config you need through YAML. Now you are working in two separate files and two different languages trying to make a change. Things almost get worse when the writer of the component and the consumer of the component are different people. Either massive horrible cludges happen to the YAML, or a weird back and forth needs to happen.