Hey John. Why you think the 3080 is much different I don't know, but I do remember our many conversations about your frustration before so makes me wonder why you'd consider the same basic unit now.
The pre-out voltage specs provided by many are but nominal values and don't reflect max values. I do think there was a Yamaha avr test Audioholics did not long ago that did show poor output, but that was a lower end model as well. Many sub plate amps don't need much in the way of pre-out voltage, some do. My Onkyo and Denon avrs have sufficient voltage for a variety of sub amps and external amps I've used them with but YMMV.
As to Music Cast that doesn't sound right that it is limited to 128kbps itself....the onboard apps in the avr may be, tho.
Good luck!
Chris