I just bought the DDJ-SX2 controller because it seemed to fully satisfy my requirements for usage with Traktor (2.9.0) and Mac OS X.
For my HW-Configuration I need 4 Channels:
Channel 1: DJ-Mic
Channel 2: Track-Deck A
Channel 3: Track-Deck B
Channel 4: Remix Deck C+D
With my Audio 8 and Pioneer DJM800 it was absolutely no issue to configure it in that way and to assign both Remix Decks (C+D) to 1 channel and to adjust volume for both Decks with only 1 Fader. Due to this internal mixing mode stuff it seems not to be possible to map the decks to different channels in the mixer. Is there any option to change this HW configuration? My configuration should be fix forever - so I wouldn´t care if I have to change the settings directly in the drivers or with some special tricks.... everything would be fine, but with the standard configuration I´m really unhappy and frustrated!