I realize this thread has been dead for a while but, one idea that occurred to me would be to add a "group" column in the drum map for kit piece. A lot of the highly detailed drum samplers (e.g. BFD, Superior Drummer, Addictive Drums) have multiple articulations/hit types for each kit piece. When you then try and use the drum editor pane in the PRV, you have this extremely long list of different articulations to search through.
I think it would be really great if you could assign different notes to a group. Then in the drum editor they would be organized together and could be collapsed or expanded similar to folders for plugins in the browser. You could even allow the drum editor to assign one note to be the default note selection for the kit piece when collapsed (e.g. closed hi-hat or side stick, etc.).
This way you could collapse everything and program a simple skeleton beat (e.g. steady eight notes on a hi-hat). Then when you focus on the snare or high hat, you expand the group and can select the different artriculations to add variation or make it sound more real (e.g. add the odd hit on the bell or rim). It's less tedious this way because everything is grouped together and you aren't bombarded with every single possible articulation in the view.
Just a humble suggestion.
Personally, I'm not sure why the drum editor is a separate editor from the step sequencer. It seems to me that you could combine the features of both in one view that would make for an ideal drum programming evironment but, that's a separate discussion...