Is your feature request related to a problem? Please describe.

Keywords only arguments are arguably clearer and allow easier refactoring on our side. When adding a new feature, we are already thinking about using * to declare keyword only arguments.

Describe the solution you'd like.

scikit-learn already went through this process and with their v1 coming up, the whole code base is already keywords-only arguments. Hence, if accepted, I propose we follow the same path.

They did it in two phases:

1. Deprecation phase with a wrapper: it takes a function and look at which arguments are keywords only. If you call the function using a positional argument instead of a keyword only argument (if f(a, *, b) and you do f(1, 2) instead of f(1, b=2)) then it will raise a deprecation warning. The function will still be working as the keyword arguments would not be enforced yet. The wrapper will convert the positional argument into a keyword argument.
2. Remove the wrapper: after the deprecation cycle, remove the wrapper and we are done.

xref scikit-learn/scikit-learn#15005