You might want to do a comparison between your int'l complex player(s) and other players in your minor league system to see how they're progressing.
Let's say both your int'l complex player and another Rookie ball player are the same age (18 for my example), and they both have similar Current ratings. If your International player has a higher ceiling, I'd promote him and take your chances. Of course, this depends on if you have a huge stockpile of talent already at the Rookie or short A level. If you do, keep your high potential player in the int'l complex for another year.
I usually pull 19 year old possible studs out of the int'l complex and get them started in my minor league system. There's usually enough room, since most of the other guys I draft end up being bums.