When I auditioned an NV10s, I was somewhat disappointed in the octave 5 sustain of its primary SK-EX patch in the SK-EX piano engine, which was shorter than for the SK-EX patch in the HI-XL sound engine. Fortunately, the NV-10s has the HI-XL sound engine as well, though the HI-XL samples (including the SK-EX patch of the HI-XL engine) are stereo, not multichannel like the samples in the SK-EX patch of the SK-EX engine.
Perhaps the multichannel samples are a little shorter to save space given the multiple channels to be stored. I wonder if this was addressed in the NV12.
It also would be nice if the NV12 USB connection multiplexed digital audio back to the instrument with midi transmitted out, serving as an outboard DAC for a computer where a VST is being used. That would enable a digital input to the soundboard speaker and associated amps and DAC. The analog input will work fine for renderings of stereo content, but I assume the NV12 does not have multichannel analog inputs.