any changes to tires and aero is going to create other unintended complications and even if a solution is found for better racing in the rain, next year there will be a new car design and new problems to overcome.
so i wonder if there are other ways to crack this egg via other technologies to consider, specifically if the main issue here is visibility (caused from the spray).
this may seem far fetched (or not even possible), but solutions involving real time telemetry, using different parts of the light spectrum, and/or augmented reality overlays fitted to either glasses or the drivers visors that they wear during wet races could improve their ability to see in both the wet and dark.
grip in the wet is never going to be as good as in the dry so that issue is one drivers will have to live with but if improving their ability to see could be done without changing a race car then surely that is the better solution.
probably should watch less Sci-F1!