One perfect-information game that's at least as hard: constructive mathematics. (Proof assistants even give it a sort of videogame-style UI.) I've been wondering about some kind of neural net for ranking the 'moves' coupled with the usual proof search.
I don't know much about Go but I'm guessing general proof automation would be many, many orders of magnitudes harder. The branching factor is huge (you can apply any theorem you want to the current goal and go down a bad path) and knowing if you're on the right track to finish a proof isn't obvious.
