The number of draws in GFs is in fact running at a higher rate than home and away games
Consider there have been 3 in 113 years which is approx one in forty. This is equivalent to one every 5 rounds of the home and away which obviously is much much greater than the reality.
In theory the odds should be about the same, so expect GF draws in the future to become even more uncommon.
There again we might see more draws in home and away, or this is just a load of drivel - ah well.