One way for the 997 to have better (in my opinion) 2ch playback is for it to incorporate balance XLR analog inputs for use with higher-end SACD players an DACs.
In doing so, you would probably also want to use a Bypass mode, but maybe add the sub crossover as well.
For direct coax digital input from a CD player, have a better quality "upsample" mode that fixes the upper-frequency harshness that occurs with the 990.