I would like to can use symbols/icons for the keywords in the keyword hierarchy. At least for the first level keywords. A good combination of words and pictures would help to quicker find the needed categories.
I additionally suggest many customizable (smooth) colors for the keyword stripes in keyword panel. I especially suggest them for the first hierarchical level, to can better differentiate the nature of a keyword branch.
Gray for all is elegant and quiet, but it isn't sufficient in large keyword collections.