I would advocate changing the default histogram bins to a data-adaptive choice in 2.0. For an example of how this might look, see info on the recently-merged astropy hist() function: http://astropy.readthedocs.org/en/latest/visualization/histogram.html#normal-reference-rules

Using the freedman-diaconis rule as the default would be a useful change, IMO (though it would require some modification in the case of weighted samples)