We are still open to the idea but the implementation should leverage the attributes API introduced in Rails 5.2 in Active Model.

We already are reserving a prop called slot so that we can do <Foo slot='bar'/> someday

given the popularity and the fact that I'm not convinced we shouldn't have first-class support for this

Even given all that, I haven't decided to close the door on offering this support in the future. If it was my opinion that we were not going to accept this ever, I would have closed the issue.