You can't move your bloody units as fast as them so your units would fire at the place where they were 'going to be' within the range or at the place they were at the limit of the range.
Utterly infuriating as a player. I know it doesn't have to be that way, and the path could be closer to strategic decision making, but it's a funny example of one of those AI decisions that wasn't constrained in one way.
In general, the smarter you make the AI, the more you have to work to give it constraints to keep it from cheesing the player the same way players often cheese dumb AIs.
In the case of an RTS, you can force the AI to manipulate a cursor and view area the same way a human does. Only give it partial information about areas outside the current view. Put limits on cursor manipulation. Maybe add a fudge factor that makes its clicks land randomly within X distance of its target, where X is based on the average speed the cursor has moved in the last half a second. That alone would make it harder for it to give orders to a bunch of individual units fast enough to out-micro a player, and you're really just giving it constraints similar to a human operating a mouse.
I made a Spring AI back in the day (it wasn't very good either).
Outside of those games, I'd say any game with competitive multiplayer could benefit from smart human-like AI. Some people play games for a challenge. The unpredictability of other humans is most of the fun, whereas playing against a typical game AI is just a matter of figuring out how it works, where it fails, and then taking advantage of that failure repeatedly. Considering the market for competitive online games, there's likely a similar market for competitive AI games.
I suspect the real barrier that is that it's a lot cheaper and easier to sick players on one another than to make a challenging human-like AI.