OTOH, I'd rather there be OOWTDI so whatever the consensus is is fine with me.
This strikes me as a gratuitous API change of the kind Guido was warning about in his recent post: "Don't change your APIs incompatibly when porting to Py3k"
Yes it removes redundancy, but it really doesn't change the cognitive load (at least for native speakers). If the blessed set were restricted to assert*, what would users of fail* do when trying to test their packages on py3k? Search and replace, or monkey patch unittest? I'm guessing monkey patch unittest, which means the change saves nothing, and costs plenty.
Note the acronym is OOWTDI, not OONTDI - using a different name does not necessarily make it a different way.