That's pretty limited on input count even compared to original Tascam. I'd think having to fuck around with cabling or having whole extra mixer just to swap what it is sent to it might be pretty annoying.
One idea to get around that (provided the whatever CPU you use there have that feature) would be USB host mode, many of the more modern devices have USB audio mode where they present themselves as soundcard, or user can then just use normal audio interface to give it extra inputs.
One idea to get around that (provided the whatever CPU you use there have that feature) would be USB host mode, many of the more modern devices have USB audio mode where they present themselves as soundcard, or user can then just use normal audio interface to give it extra inputs.