Add Vida Blue to that roster. I get the Fidrych story arc. He was pitching weekend "fun" ball and looking good. He didn't go through the grind of several minor league seasons where live arms go to die. He had his arm die at the Major League level.
What if... Mickey Mantle had not stepped on a sprinkler head in Yankee Stadium CF as a rookie and ruined his knee? He never had healthy legs for the rest of his career. A healthy, sober Mantle would have been pretty good. What if he had access to modern ortho in the '50s? Even injured, he was better than most.
Here’s an oldie. What if Herb Score hadn’t been hit in the face by a line drive off the bat of Gil McDougle?