I think the DC-2 still digitizes analog inputs(I think the MC-1 has an analog passthrough that avoids all the digital crap), so it would seem you'd be paying a good amount of money for additional inputs and DTS decoding without much of an increase in sonic performance. I guess it depends on your values, but it hardly seems worth it to me.
Also, if you value 2-channel you should look into another preamp as I've compared the DC-1 directly to some other units and it came in dead last in this category(although it's great at surround processing, so if that's your thing you might want to stay put for a while). If stereo listening is important and you don't have the cash for the MC-1 you might look at the Bryston SP1 pre/pro or maybe even the Anthem AV20. Best of luck.