Majors won is just one criteria, perhaps it is the most or one of the most important ones but it is still just one facet of a career. Obviously defining what a major is across various era's is very difficult, do we go by format and draw? Or do we consider only the top 4 tournaments of any year majors for simplicity and to be fair?
There were lots of various big events in the early Open Era this is true. Weighting them is of course difficult. Sometimes I think it would be useful to have tiers for majors to differentiate without assigning exact values. But there's so much subjectivity.
My issue with the pro majors is that the field lacked depth, in a pro type field would there have been a Del Potro at the USO in 2009? A Cilic at the USO in 2014? Would Djokovic have encountered a Querrey at Wimbledon this year? Would Wawrinka have been in the pro's in 2014 to stop Djokovic at the AO?
I prefer not to compare major title hauls from earlier era's than 1990 to now personally.
Thanks for your friendly words Bobby and the information about the French Pro. The French Pro in 1968 had a really good draw and Mccauley includes 1968 in his history of professional tennis. So I'm on the fence with regards to including it as a 'major'. Again as I said to pc1 it depends on whether draw/format determines what is a major or if it's due to status relative to other events.