Maddux, it depends on the umpire. If he's giving Maddux the corners, I'll take him over anyone. If he's getting squeezed, he's just an ordinary pitcher. Gibson, Koufax, Dave Stewart, but year in and year out, in the situation cr describes, who can possibly be better than Mariano? He's thrown that last pitch too many times to be questioned. Ford was smart. crafty, and he knew how to cheat.
Stuff pitchers, like Roy Halliday or Maddux, are dependent on the umpire calling a proper strike zone. Pitchers like Tim Lincecum never throw a strike, his ball breaks so sharply bad pitches get swung at and missed. Gibson and Koufax could win with any ump, because they could nibble or challenge, and win either way. Schilling and Johnson, too.
A single batter you have to get out? Even though he has failed a few times, I'd take my chances with Mariano. In the SIM, I think I'd go with '88 Elton Chamberlain.
Another factor that gets discounted in these discussions with the old timers is the doctored ball. Balls weren't immediately thrown out of play, and some pitchers could do amazing things with a doctored ball. Whether the ball's surface was accidentally or intentionally damaged, it was their team mates job to try and keep such a ball in play.