I've looked at Edberg's stats, and I was wondering about him. I've been deluged by work and have had almost no time to write.
First of all, going by ATP stats is hard for guys whose careers started before 1991 because we don't know if we are looking at peak years only going by such stats. My guess is that Edberg's best years re return are not available, though 1991 was a strong year.
Looking at that year, 53.87% of 2nd return points HC, 8th. Fed in 2006, 53.33%, so pretty close. Fed was 7th. But generally this stat goes down with age.
2003 might have been a great year for Fed, but the ATP is screwed up that year - 56.56% for Fed. And we KNOW that's wrong. It's wrong for everyone. But since he is listed as #7 and they screwed up everyone, probably around 53%.
That seems pretty close.
We also have to think about how the game has changed. Edberg was weakest on clay, exactly where you'd expect a guy to have more problems who is an attacker. You would expect Novak to be insanely good on clay, but for career he is #7 and is a good bit under a bunch of clay court specialists. He was an overall monster in 2011, but his stats on HC were about equal, and normally they are always lower. Clay is Djokovic's weakest surface, which to me shows that he is not essentially a grinder but more of a blend.
https://www.atpworldtour.com/en/stats/2nd-serve-return-points-won/all/clay/all/
It should not be an advantage, which is why I think we have not yet seen a player who takes full advantage of a 2HBH combined with top notch net skills. And this is a puzzler to me because today there are so many players who also have a good single handed slice.