Its amazing to see how much influence the sponge has over the ball drop test. Wouldn't mind seeing a drop test using the same top sheet with different sponges although i don't know how you would test gears.
In low rank competitions I've seen players with normal inverted rubber win like 25% of there matches and a season later they use long pimpels and win 60% ! So that is boosting pure because of material not trough skill! From that perspective I see what you mean, but when you get to know how it works it's good fun to play against a long pips player and the different kind of rubbers give TT more variaty and therefor even more interesting.
