It happens that SC2 implements certain micro AI functions for the game player, however, that doesn't stop a player from micro-ing all the units themselves, just like in SC1.
The number of units in SC2 make it much harder to micro for humans, hence the game provides help. But the human player experience shouldn't define the AI player behavior; especially one that is to learn the game on it's own.
Breaking down the goals, components, and constraints of the games, I'd actually say SC1 and SC2 are pretty similar games, especially to an AI on both micro and macro levels.
Extra waypoint actions, better pathing and the propensity to form nicer circles around an opponent targeted by an attack command isn't what I'd call micro AI. Most of that choppy feeling you get after switching to classic is because of how tiles and stacking is handled in sc2 where units step on each other's toes and slowly ease away and tiles are much smaller.
The number of units in SC2 make it much harder to micro for humans, hence the game provides help. But the human player experience shouldn't define the AI player behavior; especially one that is to learn the game on it's own.
Breaking down the goals, components, and constraints of the games, I'd actually say SC1 and SC2 are pretty similar games, especially to an AI on both micro and macro levels.