It is not only the speed of the blade that makes it challenging for a beginner. Viscaria is also very stiff which makes it more difficult to spin the ball. Putting on slow rubbers will not help making the blade more flexible.
Some people want to believe, and make everything possible to push that belief on others ! that it's easy to use a fast blade with slow rubbers, but it's not the case at all: the blade is the most important component of the racket, it's from the blade that all the important informations such as vibrations, dwell, sense of control and speed (reaction so), come. It's like having a powerfull car with small tyres on it : you won't be able to feel how the car reacts, you won't be able to feel the grip, that's why family cars have tyres made for everyone so that EVRYONE is able to feel and control the car, and Ferrarri/Porsche/Bugatti ones have bigger ones specially tailored for competition by Pirelli or Michelin, tailored for people that have a greater experience with that kind of vehicles, people that have a better feeling of the road. And in that case you need bigger tyres so that you can either feel the car/road + transfer its potential to the road.