Agree on the combined cables. Saw a DJ who had them custom made. I think there are some cables like this available commercially.
With my BK9 I could get away without a mixer because it has a mic and aux. input so the keyboard becomes a simple mixer. Not much tone control however.
My Yamaha 512, even in its road case isn't too bad to move and my Carvin XP800L is so small it fits in a gym bag with the speaker cables so its not that much of a pain and I like the flexibility.
Since you posted about the Yamaha mixer I thought you used one. Would be nice to drop a piece ( powered mixer ) but other stuff has to go first.