I think that the ability to decode DSD would be appropriate to include, but there's a wrinkle to it that people may not always think about. Unless you have a bypass mode that skips the DSP section entirely and DAC's that can convert DSD directly to analog (in which case you will need to be content to havd absolutely no bass management or other DSP), that DSD bitstream is going to be "decoded" to LPCM. Most SACD players that can output DSD over HDMI can also convert it to LPCM, making DSD support a nice touch but not a "necessary" feature.