Agreed. Poker is another interesting case of "partial information" game. There is some discussion of this in the links below. I suspect that AlphaZero could make a decent poker player with a non-trivial amount of tweaking.

1. https://www.technologyreview.com/s/601157/could-alphago-bluf...

2. https://www.quantamagazine.org/why-alphazeros-artificial-int...

I wonder what would happen if you made DOTA totally observable. You could probably reformat it as 5 pieces for a player instead of 5 people on a team or the like. It would probably change the game too much to be recognizable as the same, but I think it would be an interesting experiment if nothing else.