I think that would likely be redundant with the histogram.
I am afraid I do not get you. I mean histograms should be considered when it comes to increasing number of MCV entries (at least for numeric/timestamp values). With histogram lower number of entries could be sufficient to get reasonable accuracy of estimations.
I have no idea how to decide between automatic switch between histograms and MCV. It might sound crazy one could compute both histograms and MCV and use them both (and pick an average of two estimations :) )
Regards,
Vladimir Sitnikov