Shadow softness can be achieved in Esprit, by applying a softness % to any light, in the object attribute manager ( right above the camera preview). What I usually do is reduce the shadow % to about 75% (right click the shadow button in the manager and reduce in the pop up window), and give the light 5% softness.
You will need more antialiasing with softness on, because soft raytraced shadows produce noise artifacts in the shadow edge.
But it is absolutely possible to get this effect right with Esprit.