I've been watching some tennis from the 90s. I am trying to get a visual impression of court speeds relative to today by comparing baseliners from the 80s, 90s and 00s, which I may report at some point if I arrive at any conclusion.
Reading through this thread, I must say that I find Courier's forehand pretty underrated. It was an awesome and beautiful stroke, more economical than most, no floriture, at least as powerful as Sampras', but much more precise and consistent. Maybe the underrating I observe is due to his relatively short stay at the top. I am referring to his forehand especially when he was a top 3 player in 91-93.
Best forehand by the decades I am most familiar with:
1980s: Lendl, by far
1990s: Courier, by far
I would have a hard time choosing between those three, but I could very well choose Courier's today.