It doesn't require creativity. It just requires a deep understanding of the game. The game itself has a very restrictive set of rules. It isn't creative at all. BTW, game playing isn't AI at all. Computers are good at playing games with a restrictive set of rules. In fact that is the one thing they are best at: computers LOVE rules and require them to perform any task.
The comparison between games that have a restrictive set of rules and those that do not is the wrong comparison to be making.
The reason WHY computers tend to do well at game with restrictive sets of rules is because they're able to take those rules and fashion them into a set of all (or at least a significant portion of) possible positions that are going to come up in the game that they're playing.
That's not a valid solution to Go because the number of possible positions, even in the context of an individual game, is too vast to be able to use a brute force approach. Despite having a "restrictive rule set", just like chess does, Go does not allow for the same kind of "AI" (which isn't really AI at all) to solve it. The comparison here should be between games where brute force is possible and games where it isn't. The size of the rule book is meaningless.
So no, just because you can write the rules on one page doesn't mean that you can just unleash a supercomputer at it and suddenly it beats grandmasters. That happened in chess. What's happening here is much more profound.