One of the rule changes being discussed is to require any pitcher to face at least 3 batters before being replaced, just to stop the “one batter” substitutions. (which are more common today apparently, back in the day I remember it happening rarely, like when a pitcher got in trouble quickly or got injured, there was one bullpen guy who could warm up quickly, and then you’d bring in the guy who took longer to warm up).
I would love to see that happen.