My judgment call is that the keyword-only change can be made directly, that the costs and clutter of deprecation and delay aren't worth in it this case, that the nature of the "verbose" and "rename" arguments puts this in the rare-to-non-existent category, that any remediation would be trivial (easier than shutting-off a warning), and that the user's come out ahead with the cleaner cut-over in this case.   There's no value in being pedantic on this one, some judgment is required.