We need old dampers that are bad in a new way?

One thing that happens as a piano ages is that the dampers move off to one side, or wear more on the edges, so that the unisons are not damped evenly. In other words, some unisons are damped more than others. No one unison string may be completely undamped, but some have higher partials that die more slowly than the partials on other unisons under the same felt, and the decay of the single string may be longer. It's part of the older piano sound, from what I can hear. I think I need it. The control would be something along the lines of "Shift damper to the right or left." Or "Decay on the outer edges." The effect of the change would differ as the Unison Balance was changed, too, of course.