A soggy (or juicy) strawberry rhubarb crisp is simply due to not using enough flour to thicken the juices. Depending on how juicy your fruit is will depend on how much flour you should use to thicken it and how juicy or thick you like your filling. For this recipe approx. 1 tablespoon flour will lead a juicy filling and 2 tablespoons flour will lead a thicker filling. Another factor is the bake time. If the crisp is underbaked it will be soggy. The right bake time will thicken the juices and crisp up the crumble.