The thing about the Shane Warne ball that makes it so special is that the ball is the exactly perfect legspin delivery.
Sure there were bigger spinning balls. Sure there were balls that had a more "important" impact on a series. Sure there were balls that were technically more challenging to bowl.
But the "ball of the century" was a ball that, taken in isolation, was a work of art. It was and still remains the greatest advertisement for leg spin. If there was a single delivery that you could show to demonstrate everything that makes leg spin a beautiful part of the game, and deadly when implemented correctly, it is that delivery. There may have been balls that were more "important" to a series or balls that were technically better in one aspect or another. But THAT ball, well, that ball captures the imagination every time you watch it. It is the perfect ball. It combines flight, dip, drift and spin utterly perfectly to completely bamboozle the batsman. It is the ball that every leg spin bowler hopes to one day bowl. It is not just the massive turn that makes it so special. It is not just the perfect line and length that makes it captivate the viewer. It is every single technical detail, dancing in perfect unity that makes it so special.
And all of that is ignoring the impact on the psychology of England. That ball totally demoralised a nation for over a decade. It gave batsmen worldwide nightmares. It went down in folklore due to the combination of the technical brilliance and the theatrical timing of the ball. The Ashes is the biggest, most revered series in test cricket. And when Shane Warne bowled this ball the brilliance of it announced to an entire generation of English that they had a new pantomime villain, one that was worse than all those that had come before. One man who would continue to humiliate and shame their proudest warriors from that ball until the day that he retired.
And it was a nightmare come true for the English. It was a legend born. It was the true origins of the man they nicknamed "Hollywood". And it was the dawn of the era of English men being shamed by the greatest leg spinner of all time.
One could argue that there were technically better balls in one aspect or another. But for those who saw it live or watched it on tv, it will truly remain etched into our memory as the greatest single cricket delivery that we have ever witnessed.