DAVIE, FLORIDA: After a 33 year career as an NFL head coach in which he won 347 games, more than anyone else in league history, Don Shula will step down as head coach of the Miami Dolphins. In 26 seasons as the Dolphins head man, Shula won two Super Bowls, and lead his 17-0 1972 team to the only undefeated NFL season ever completed. But with no league championships in the last 22 years, Dolphin fans had grown increasingly impatient and called for Shula's ouster. "Everyone in South Florida, the media and the fans, say that it's been a long time between Super Bowls and that the game has passed him by," says Sports writer Steve Wulf. "There's very little compassion for him. But Shula deserves to be cut a little slack. He hasn't lost any of his passion for the game. Everyone says he still works hard and keeps the same long hours he always has." Wulf notes that team owner Wayne Huizenga put his coach in an untenable position Wednesday when he said Shula had to fire all his assistants: "With the season coming on, Shula would have to hire an entirely new staff for next year, which would have made it much more difficult to be successful." Speculation as to Shula's replacement has focused on Jimmy Johnson, who led the Dallas Cowboys to Superbowl victories in 1993 and 1994. Johnson is currently putting in time as a Fox TV football analyst. "It's most likely Johnson," says Wulf. "Huizenga wouldn't let Shula go if he didn't have a pretty big name lined up to replace him."