[daymanstep]

Recalculating the path every game tick is too expensive. What brood war did was to just have units wait for a second when they collide with something before recalculating the path. This resulted in horrendous "traffic jams".

It's also why Brood War players got into the habit of spam-clicking, because the game would recompute paths every time you issued a command, so spam-clicking resulted in smoother movement.