This thread presents the very best of LetsRun--thank you very much to Drew, Mr Daniels, and old guys etc.--being one I can say that. Unfortunately with any great thread you end up with trolls like Perry. Please do not take this as any dis to Kip Keino. Keino was truly an all-time great runner, who ran one of the greatest efforts ever at Mexico, but he was not the miler that Ryun was. As someone previously pointed out, his best distance was probably the 3000.
There is no doubt that Ryun could have run faster--simply put him on a Mondo track during any of his world records and he would have gone faster. If you would have given him multiple pace setters the day he ran his 3:51.1 on the cinder track, there's no doubt he could have gone faster. He was simply one of the most gifted milers ever--if not simply "the" most gifted. It's really hard to say how fast he could have run.
The only runners I've see approaching his talent level are El-G and Steve Cram--who I think was the best miler of the great Brits. What is interesting is that all three were actually very similar. They were very fast at the end of races, but they weren't burst runners. As Drew pointed out about his Dad, they all were wind it up long, fast kickers.
One other observation on Ryun. I actually think the most incredible race he ran was the win at the AAU meet versus Snell as an High Schooler. Alan Webb's 3:53 run was great, but for perspective, that would have been like Alan beating El-G and running the 4th or 5th fastest time ever--basically 2 seconds from the World Record. The clip never fails to inspire my runners.
Finally, a simple thanks to all for the great thread!