Well, a soundcard wouldn't even really be visible, other than a "SC" addition to each of the matrix knobs, and a USB connection on the bottom (run an extension, I hate those on the top easy to break USB connectors!).
It would simplify booths, and negate the entire connecting/unconnecting necceisty.
Although these days I really just prefer playing on the 2000's with USB sticks, no laptop...
And YES on the knobs! Those nubs were great!
They really could use non-plastic pots on the EQ's as well. The isolator on the MP2016 itself uses high quality pots, the XP uses plastic ones.