I can confirm I also experience this regression with recent update (Plasma 5.5.95). Setting it to 80 via "synclient VertScrollDelta=80 HorizScrollDelta=80" gives desired result, but it is impossible to set these values via UI.
I can confirm I also experience this regression with recent update (Plasma 5.5.95). Setting it to 80 via "synclient VertScrollDelta=80 HorizScrollDelt a=80" gives desired result, but it is impossible to set these values via UI.