I never got a good feel for why some preamps made the list and others did not. The PAS-3 I can understand as well as the Citation 1. But the ARC SP-11?? The 10 was a better unit IMO, but both had regulator design issues that were profound (prone to oscillation). If ARC were to be included it would be the SP-3 although I would prefer the Citation any day. The CAT was one of the first preamps I ever heard that was really neutral and lacking 'tube tubbyness', a problem in many preamps prior. Another favorite was the MFA Luminescence.
I think a preamp that was overlooked was the Berning TF-10. This was one of the first preamps to have a vacuum-tube direct coupled output (and certainly influenced the introduction of our MP-1 preamp, which had/has a balanced direct-coupled output in 1989).
FWIW, the MP-1 was the world's first balanced line preamp, being fully differential throughout, and pretty much introduced balanced line operation to high end audio. It is significant for that reason alone. BAT founder Steve Bednarski was an early owner and influenced the BAT concept (use of the Circlotron circuit). Not sure how others see balanced lines, but in the last 23 years its gone from a curiosity to having main stream support by a lot of bigger players.... not meaning to blow my own horn here but if you want to show an influence on the industry that one is indisputable.