Many people complain that SNL plays out the joke of a sketch until it has worn out its welcome, as it were. SNL has even poked fun at this in a few sketches.
Here is my formula for a 'new and improved' SNL for the laughs of tomorrow.
s = sketch(es) d = duration l = laughs
s * d = l
1.5s * .75d = 3l
Having one and a half times more sketches at 3/4 of the length would make for three times more laughs.
2s * 1/2d = 10l
Having twice as many sketches which are half as long makes for ten times the laughs.
This graph more or less should explain it all: