I'm going to feel like a pedantic jerk here, but even the wandering ghosts in the original Pac Man could be predicted to a degree. Blinky would look ahead to see where you might be going, and then try to cut you off by turn a corner to take a shorter route. This was especially true when you got slowed down by eating dots, or if you were going after the fruit. Pinky, by contrast, simply followed you move for move, taking the same straight paths and making exactly the same turns. What ghosts in the original Pac Man never did was double back on their own paths, except in response to the power up.
There's also the matter of the angry and alerted modes (as you've described them) also being present but not visually indicated in the original game. It was possible for ghosts to lose track of you, especially if you went through one of the one-way paths. And they had to remember to kill you, since it wasn't a matter of unconditional sprite collision. In particular, Inky would spend a lot of time chasing you down and then simply forget to issue the kill command, allowing you to sail right through him in uncommon circumstances.
To your original point, I would say 'wandering' is a perfectly acceptable correction.