I personally like that Phoenix is kind of a middleweight framework, but at least one of batteries you mentioned as missing is being addressed. José is working on an authentication solution built into Phoenix.
Authentication is hard, but to be honest, building your own authorization framework is actually really easy in phoenix. Mine is about 80 LOC, and most of it came from the phauxth generator. Granted the default is rather broad, so I've added a few functions to handle some role specific stuff.
