If we go back to Pig's heyday, a lot of Pig's matches were won by the very simple expedient of hitting someone with Disease, switching to W/D after the clap and killing them with it because they didn't defend correctly. You wouldn't consistently get many people over 1700 with that these days, but people high up on the ladder such as Melchior, Gorby and Anduril all fell to it back in the day. If we look at my three matches with Pig when I was assuming the top of the ladder, in one of them he actually casts Disease at an ogre of mine to kill it -- a hideous misjudgement of initiative. Maladroit was very poorly understood, and people regularly opened DSF/PSD in Maladroit on both sides. About 80% of the ladder or more were not planning to handle disruptions gracefully; I remember my shock on first playing Pig when the disruptions I fired at him were incorporated neatly into his spellflow.
It was no accident that Pig never recaptured his top spot nor climbed much beyond 1900 when he did improve his game. He completed almost all his spells and expected you to complete yours; but the new era was one of complex shadowcasting. He hadn't had to think about openings in a long while; now everyone had their own signature variations to worry about when playing Maladroit. He measured the success of his moves in damage; but the new breed thought in terms of initiative and flow. When people developed new and imaginative tactics, he was completely unaware of them, and didn't incorporate them into his game when he encountered them.
You mentioned Pig's strength with monsters, but to be honest I found him far inferior to ExDeath in that regard. ExDeath was one of the strongest of the new breed, strategic enough to predict the moves of Tchichi and Pig, and daring enough to gamble at critical points that they would react as he predicted. Tchichi however was evolving and adapting, and while he was sliding further down the rankings he remained more competitive than Pig.
By this stage standard tactics and strategy on the ladder were already a good deal more advanced than they had been. The value of monsters was now well appreciated, and the understanding of the importance of initiative was significantly closer to that we have today.
The next part is pretty much the Golden Age of Warlocks, and saw the rise of Yaron and Prioli. Yaron in some measure is responsible for the development of many of the most sophisticated tactical analyses, for he was exceedingly gifted at taking a weave that had been used only once against him and incorporating it in his own game. Gaining an edge against him required much inventiveness. Prioli, on the other hand, wedded a better appreciation of strategy and tactics than ExDeath had to the same daring in gambling; it's possible that he was somewhat lucky, it's possible that he was adept at psychology, it's even possible that when he made his climb the top of the ladder had fallen into predictable ways, but it gave him a long winning streak. I was not around to see the end of it, if it ended.
When I returned, things were very different. Strategy and tactics hadn't advanced at all since the Golden Age -- in some respects they'd even regressed -- and Tchichi was sitting alone at the ladder's top with a huge ELO gulf before you got to his nearest neighbours. Fortunately, as we all know, things have been shaken up since then, and I think we're back at a stage of advancing tactical sophistication.