This is exactly what I was looking for as well. Also, tying random playback direction to all the other randomness makes it less useful. I occasionally like having 100% random note order/direction for some things in my patches, but I would almost never want to have 100% velocity or gate time randomness/probability with it. Separating the randomness of playback direction from the other things and/or having separate randomness/probability settings (in MIDI Control Center?) for the different parameters would be very helpful.
Also, the drum sequencer isn't only used for drums. Having random order for the drum sequencer (again, as a playback mode, separate from the other randomness) would make the drum sequencer more powerful as event triggers.
(I don't own a BSP (this is one of the things keeping me from buying one); forgive me if I have anything wrong.)