That's a bit of a simplistic interpretation, IMO. If the intent was just to supersede the functionality of one launcher with that of another, upgrading the Google Now launcher would make more sense (especially as the functionality of both is actually within the Search app).

I have a feeling that a (perhaps only slightly) more significant refactor is in the works, for example making the Google app itself the "official" launcher, or doing away with a separate "launcher" app altogether in favor of emphasizing the voice recognition capabilities.

EDIT: It looks like what Google is doing is actually making the Google Now card functionality available through a new Search Launcher Services API to official Android Partners: http://www.androidcentral.com/why-would-google-pull-google-n...