I mean, obviously one wants to quit doing narrowband as soon as possible; it misses almost all the energy in many consonants, harming intelligibility, and everything including vowels sounds flat. Mediumband is much better but still an obvious degradation. But wideband is quite good and I'm happier with an 8KHz lowpass than I am with most kinds of distortions. SWB speech is frequently non-ABXable from fullband, since above 12K there's so often little other than noise of dubious audibility.
So it's surprising to find that the encoder will now be spending bits at rather low bitrates on coding 12-20KHz rather than spending more bits on accuracy in the frequency range where the formants and most of the consonant energy are. I wonder what kind of listening tests etc suggested making such a move.
Down the road I wonder whether something like the WaveNet codec2 decoding demo will end up making SBR, hybrid mode, etc mostly obsolete for speech.