In my workflow, one feature that I think could be very useful is transform last stroke.
What I meant with that: once you made a stroke that you think is perfect and you want to preserve it shape, but change scale/direction/position (and maybe some other transformations, like opacity would be useful, too) you use this feature and position your last stroke exactly where you want it.
This could be achieved by creating every new stroke on new layer and merging it down, but that is kind of hassle.
Maybe there is already such a feature in Krita? If not, what are you thinking of it, would it be useful for you?