I think it would be fairly easy to add a few control sliders to be able to adjust training dummies in practice mode. It would be incredibly helpful to be able to simulate actual DPS against real targets you may be facing that way you don't have to work out calculations to figure out DPS between items. Right now it is impossible to compare DPS between any builds that contain % health damage against builds that don't. % health builds do crazy damage to dummies with 10k health.
Having a slider or input to be able to adjust health, armor and mr would be incredibly helpful. If you really wanted to get fancy being able to give actual items to the dummies would be useful as well, but just having the health/armor/mr inputs would be great!