Some would be willing to argue that Rivera either wasn't by far or wasn't the best relief pitcher in the AL, nevermind best pitcher.
For me, a RP has to be astronomically better than the top SP (and by that, I mean Gagne/Eck caliber stuff, and that's a maybe) to justify getting the Cy Young with as low as 1/3 of the innins.
Just because Rivera got the luck to be placed on a team that wouldn't have made the playoffs without him (or Gordon, or Johnson, or Mussina, or Sheffield, or Rodriguez, or Jeter, or etc.) and Santana had the "luck" to be placed on a team that couldn't hit and had no support behind him. Just think, if he got three wins during his 23 IP, 3 run stretch over 3 games, he'd be 19-7. The team argument sucks, and is even worse when you're looking for best pitcher, not "most valuable" ().
"I remmeber hearing that Clemns would win 25 w/ the Yankee O in '99 and he won 14 and that RJ would win 20 easily w/ the Yankee bats behind him and he won 17."
That's because for the first half of the baseball season, RJ pitched at the same caliber of Matt Clement, and not of Randy Johnson. If he won 17 with an ERA of 3.79, and Santana won 16 with an ERA of 2.87, it shows the value of a good offense. FWIW, Johnson had 5.62 Runs of Support when he pitched (good for 18th in baseball). Johan Santana almost had a full run less (ironically, almost the same distance between their ERAs), and he was 24th in baseball...among pitchers from age 21 to 27. 58th overall.