It also depends what the "most important papers" actually are. What is it that makes something a breakthrough?

Suppose I'm analyzing a species of bacteria with some well-known techniques and I discover it produces an enzyme with promising medical properties. I cite some other research on that species, I cite a couple papers about my analytical tools. This is paper A.

Other scientists start trying to replicate my findings and discover that my compound really lives up to its promise. A huge meta-analysis is published with a hundred citations—paper B—and my compound becomes a new life-saving medicine.

Which paper is the "important" one? A or B? In the long run, paper A may get more citations, but bear in mind that paper A is, in and of itself, not terribly unique. People discover compounds with the potential to be useful all the time. It's in paper B, in the validation of that potential, that science determines whether something truly valuable has been discovered.

Was paper A a uniquely inspired work of genius, or is science a distributed process of trial and error where we sometimes get lucky? I'm not sure we can decide this based on how many citations paper A winds up with.