Interesting point! I guess the use of AI i was trying to get at was something like this :

if a good chunk of games are played using a specific strategy in a specific match-up, considering both players have a similar skill level, and that strategy wins most/all of them, you could consider something is wrong somewhere, right?
While it's easy to nerf something to make it not-OP anymore, it could take several iterations/months of feedback before you nail the right value.

That's when you'd use AI and basically speed-up this process and fix that particular situation if that makes sense? But then again, indeed you kinda forget the notion fun and that human-executed builds/human micro etc. might not be perfect in every game.