While I tend to prefer the more "pure", unadulterated flavour of fresh plums, you may want to try adding a teaspoon of Kirsch to the purée going into the ice cream base. The small quantity does not really make your ice cream "alcoholic" in any significant sense, but the addition of Kirsch amplifies the fruit flavour, making the tasting experience somewhat deeper and more complex.
The yoghurt in the recipe adds a certain tart freshness to the final flavour of the ice cream, and also avoids that the fruit flavour becomes "dulled" by too much cream.