Found this piece from the legendary Bill James on making the story of a fictional yet plausible baseball player entirely through stat-lines. Although he doesn't use the words "alternate history", he does theorize about how "you can make up a universe with its own rules", such as the 1960s being a hitter's era instead of a pitchers one as it was IOTL. James admits a giant book of fictional stats, though obviously appealing to him, would not work now. I personally don't think it ever could, because even baseball stat nerds would prefer to look at actual history, and they'd inevitably start nitpicking the figures to death.
Me being a big-butterfly person in my own AH writing, I like how he does emphasize interconectedness, complexity, and making it feel organic.
Me being a big-butterfly person in my own AH writing, I like how he does emphasize interconectedness, complexity, and making it feel organic.