I don't think computers will be ever calling balls and strikes. At least we will never see it. Video replay for homeruns was desperately needed and has been extremely useful. Any form of video replay will never be on balls and strikes either. I would be for a limited number of challenges/game like 1 for (out/safe) or (catch/drop) similar to that of football but not giving any extra for getting the challenge correct. The manager would have to use the challenge very wisely.

I’m armed and I’m drinking. You don’t want to listen to advice from me, amigo.

-Max Payne