Well for an educated traveler who knows that s/he has to transfer terminals, it shouldn't be that big of a deal. You have to re-clear security either way. And I presume there are probably a handful of folks connecting to CoExpress out of Terminal A, so this is incrementally easier for them (one fewer stop on the monorail).
I do 100% agree that the EWR Airtrain/Monorail is a complete and utter travesty.