They need a real solution for that, because current wet tires face quite complex problems. Indeed, the idea of rain wheel cover to reduce water spray was proposed and several teams have tested it, but the idea was rejected by the FIA for safety reasons and the rain wheel cover was not effective enough to reduce spray significantly. Another reason is the big aerodynamic problem, which affects the balance of the car and performance. So with these considerations the project was stopped. However, the FIA must find another solution to this problem because in extreme conditions the visibility of the drivers is very bad, maybe redesign the tires and redesign the floor & diffuser.
Yep.
The only solution is to cover the tyres since fender has been rejected.
But again covering the tyres is against the nature of "formula1".
As you said is also an aerodynamic advantage covering they tyres.
Tyres are actually the biggest enemy for engineering since they make the air dirty around the car and wings has the job to deflate the air around tyres.
Now if they cover the tyres the air around them will be cleaner and a revolution of wings stats consequentially...