That Open AI showmatch was pretty impressive(in terms of how the AI played, the matches were terrible).
The AI still has some bugs to work out(double warding, smokes are 100% wasted everytime by just smoking in range of heroes/towers or just smoking then attacking a creep) but their teamfights is just way too good. Besides the near instant hex reactions which makes most blink dagger initiations pointless, the fact they'll instantly punish anyone who's very slightly out of position gives them such an edge. It's also interesting how they use very different timings and general strat than the usual human teams. They play to win early, they give their supports like Lich xp early on, so he can nuke the shit out of everyone harder, and aim to close at 20. That looked really oppressive and the fact it feels they're everywhere all the time, everytime someone steps in the lane to farm, here have some nukes in your face motherfucker. They also don't flinch. You try to scare them off by turning around and nuking them back and humans would just generally retreat and play it safe, but the AI knows, they just keep autoattacking and kill people under towers.
I'm sure there's some tricks you can do to make them bug out and what not, but I'd expect next year they'll probably have illusions, couriers and most heroes in the pool and it'll be hard for a human team to actually beat the AI in an "almost normal" game of dota. Their gameplay is just too clean.