I'm not sure where the Polaris architecture is crap comes from and also Vega is a different architecture, hence the different name. Polaris 11 and RX 470 (P10) are still to come and should by all accounts show much better power usage.
It is about on par with Maxwell performance per watt which is on 28nm. Now we know that Samsungs 14nm isn't as good as TSMC 16nm but it surely cannot explain the massive delta between AMD and Nvidia currently.
AFAIK Vega is GCN 4.0 as well and isn't a new architecture. AMD / Samsung / GF might learn something about the process node from the rollout of this chip to help improve Vega - if they don't they will need a 450mm2 chip that that consumes 275w to compete with the 1080.