The courts could be slowed down but its not like the Anderson/Isner/Querrey types are cleaning up.
Quite.
If they were and such players were most of the top ranked players and seen as the way forward then that would be problematic. They aren't so it isn't really.
I guess an Isner type with rather more strings to his bow would be a bit scarey but at least he would have more strings to his bow.