Once you have multi-velocity drum sounds (that change the actual sample played as you hit harder), there is a very significant difference between raising a drum's volume, and raising the drum's velocity.

Having an edit system that allows BOTH is just about essential, IMO.

Donny is right in that Roland made doing this easier than any other arranger, and it makes a RADICAL difference to how easy it is to tweak conversions and user styles to your taste. After all, if something is easy to do, you are likely to want to do it. Make it hard, and you are most likely to not bother (and suffer one way or another from the drop in sound quality)....

BTW, all Roland E series arrangers (E50/60/80) as well as the G70 had this capability. You don't have to get the TOTL to have access to this.