I'm surprised they felt confident enough to lift a lot of the restrictions so soon. A lot of them seemed like big game changers I wouldn't expect the ai to be able to exploit so easily. Especially the introduction of Roshan and invisibility, they mention implementing some randomization, it seems like it would take quite a big commitment in terms of resources to take Roshan where the AI wouldn't even realize the benefits immediately (namely the Aegis, the XP and gold they would have to value against the loss from farming/taking towers).
The introduction of the other heroes also comes as a surprise, I wouldn't have expected them to have the ai utilizing new abilities. They don't mentioned how they are picked, other than the ai having a random draft of them (does the ai pick their composition?)
I wonder if the reward mechanisms factor in denying resources from the enemy team. A lot of the time it makes sense to take Roshan just so the enemy doesn't get the opportunity to.
I think that'd be an even harder behavior for the ai to come to though, since they'd have to recognize those benefits for the other team and their origin, and then finding that taking Roshan prevents those benefits. I think that's a next step after discovering the benefit of taking Roshan.
Same argument applies to pushing and defending towers, getting rax etc. Assuming that the devs did not hardcode rewards for those objectives, then the AI surely already has to 'understand' events that impact the game in long term.
I think you're right about it being more about denying the enemy team. IIRC, in the last update they said that the bots tend to prioritize denying creeps and taking objectives over getting perfect last hits in lane.
The introduction of the other heroes also comes as a surprise, I wouldn't have expected them to have the ai utilizing new abilities. They don't mentioned how they are picked, other than the ai having a random draft of them (does the ai pick their composition?)