I agree, I really enjoy using dc.js but it would be even better if a future release already came loaded with a more modern style up to date with some shinning competitors.
and @gordonwoodhull
As for a default color scheme, I think using one of the categorical schemes from d3-scale-chromatic would be appropriate. There are also one or two places (like the heatmap) where we use continuous color schemes, and any of the diverging color schemes should work. I'm open to other ideas too!
This will finish a process Deepak started in dc@3, where we deprecated d3.schemeCategory20 and copied those colors in for backward compatibility. There is still a warning message which people ask about every once in a while. (#1664 / #1564)
Reference - conversation with @plourenco
and @gordonwoodhull