I think it is likely that a high end 2-channel preamp will still be better than the MX170. While the MX170 is going to be a very excellent HT processor, it still uses op amps for all analog stages (both input and output stage).
I think the only HT Processor that I would consider being in the 2-channel analog preamp level is the Bryston SP3. It uses their fully balanced and fully discrete analog stages for BOTH input stage and output stage. That being said, it is my opinion that the DSP/DAC board is compromised and is not to the level of other devices (such as Krell, etc.). The SP3 has just about the strongest and fullest bass I have ever heard from a processor, though.
I think the only HT Processor that I would consider being in the 2-channel analog preamp level is the Bryston SP3. It uses their fully balanced and fully discrete analog stages for BOTH input stage and output stage. That being said, it is my opinion that the DSP/DAC board is compromised and is not to the level of other devices (such as Krell, etc.). The SP3 has just about the strongest and fullest bass I have ever heard from a processor, though.