No i never seen koufax pitch but to say he is the 3rd greatest pitcher because of a 5 year span is not means to make him the 3rd greatest ever. If thats the case then maddux should be #4. he had a 5 year span where he was just as good. and maddux had very little run support. not saying koufax isn't among the best ever, but hardly #3. Randy johnson and Pedro could be thrown into the mix also. Different era for sure. Todays pitchers do not get the amount of starts that the old timers had. Plus today there is more emphasis on a setup man and a closer.
What a dream it would be to see if the pitchers of the past could put up staggering numbers as in the past and vice versa.
As far as #1 goes Johnson numbers are unreal and is deserving of it. Matthewson also is right, but after that I see a big difference.