The cdrom game allows for very complex specifications on when to use a relief pitcher such as score, outs, batter type among other things. Plus for each of these factors you can list 50 combinations that would theoretically cause HAL to bring in that reliever. Utilizing it would result in a rather complex screen that I think would be confusing for most and in my opinion would require 8 or 9 man bullpens like exist in real life. And you can easily spend much more time setting up a super hal bullpen than you do with all other functions of building a team.
Plus I suspect most would use the interface to make sure 2 or 3 nickel relievers are never used forcing a single reliever to get 400 or even 500+ innings. I could see someone with a Babe Adams type having a 5 man pitching staff where only those 5 were ever used.
I suspect between how it could be used to twist the game by some combined with the complexity for those who want to use it in a legitimate way would chase off a very large portion of the community.