Ah, I hadn't seen the Hellblazer solution.
So here's a list of reasons I could come up with why there should be two Batwoman titles and why there shouldn't:
•Two #0s in one title could be confusing
•The relaunch clearly canceled all ongoing titles and relaunched a number of them with new #1s. So following that pattern, the pre-relaunch volume of Batwoman was cancelled, even though it only reached issue #0, and was relaunched, along with every other title, as a new volume with a new #1
•Two "Batwoman (2011)" titles could be confusing
•The current volume has the same initial creative team as the original #0
•The first few issues were solicited -- pre-relaunch -- with the same plot and covers as what appeared when finally published post-relaunch
•The pre-relaunch #0 was reprinted, along with the first five post-relaunch issues, in a Batwoman volume 1 collection
Also, I checked to see if the two volumes had the same ISSN number, but the pre-relaunch #0 didn't have a number, and the post-relaunch series does. This doesn't necessarily suggest they're different volumes, but I didn't think it should go in either column.
Anyway, I agree that there's no need to change anything before the issue is published, but I thought I might as well bring it up.