There was the brief period around 1981 where the consensus was that Hana Mandlikova (still only 19) would actually have the better overall career than Martina Navratilova (stalling at 24), as Hana had already matched Martina's 2 majors at that point, plus Hana had reached 4 consecutive major finals (1980 US Open through to 1981 Wimbledon).
Interesting.
I watched some youtube videos of Hana over the past day or two and when she was on, she played with tremendous ease and flair. She could generate a lot of pace yet she also had tremendous touch and feel for the ball as well. But wow, she had a pretty volatile temper. And when she was off, it wasn't pretty. But it's hard not to be in awe of her abilities when she was on.