Am glad you posted the format, it just made my decision ten times easier. Since it was a round robin format, then no, sorry but it doesn't go above the slams. Was already leaning this way anyways, because people had the choice to play any of the slams if they chose to.
It wasn't a round-robin format. The Dallas WCT event(which offered far more prize money to the winner & had far better attendance-bigger stadium as well- compared to the French Open in the 70s) was a single elimation 8 man event, best of 5 all rounds. Players had the choice to play slams, for sure, but why would they play slams that had no prize money, news coverage, or fans in the stands when WCT offered all that? Just so fans 30 years later could compare them to Federer or Sampras?
Like I've said many times before, you can't use the standards of greatness today compared to back then. Johan Kriek beating Brian Teacher in 2 AO finals doesn't seem quite as significant as Borg/Connors/Mac playing each other in Dallas Finals at the same time.
Plus you couldn't even watch the French Open on tv in the US in the 70s. You could watch Dallas WCT though. If it wasn't for the '72 Laver-Rosewall Dallas final you probably wouldn't be watching any tennis on tv today. It was that important an event to the growth of the sport.