Two things stand out to me, and they have nothing to do with micro: The AI consistently did a 'deathball push' strategy, where small early advantages snowball

Two things stand out to me, and they have nothing to do with micro: The AI consistently did a 'deathball push' strategy, where small early advantages snowball and they pushed hard to exploit that early advantage. One of the things that enabled that was that resources were more evenly spread across the team, allowing the heroes that were strong earlier to do something with that advantage. Competitive and casual ranked play hasn't switch to always do deathball, but there is a marked increase in the amount of resources that early-timing 'support' heroes take, they are a lot greedier than before OpenAI. (as pointed out by a sibling post) It's unclear if that is either because of lessons from OpenAI-five, or because of the balance changes (there is more resources to be had around the map these days). The second thing that stands out is that the 1v1 OpenAI and the 5v5 OpenAI did buy a lot more of 'consumable' items, mana and HP potions basically. These were considered too inefficient before, people tended to prefer items that gave a more over-time regeneration and long-term efficiency. What the bots did was /constantly/ ship consumables over, which was kind of surprising at the time. It used that consumable resource to either force an opponent away from xp/gold resources (lane, jungle) or allow it to stay after aggression. Once pros started buying a lot more consumables, casual players quickly followed suit.