Interesting and workable. Especially if he practiced it. Mobs, like most of us, are creatures of habit and they probably are predictable as to how/when they follow a target.
Oh yeah. Super predictable. Doubly so back in the day. EQ had some "odd" pathing rules. And you could often find spots where mobs would take what appeared to you to be a circuitous route to get to you. There used to be a "seam" in the mob pathing on the first floor of Unrest. Basically, there was a room (dining room I think?) with a hallway running along three sides, and three entrances from said hallway, each entering from a different direction (call them North, East, and South). If you were standing in the room just inside the South doorway and aggroed the mobs, they would run straight at you, but if you backed into the hallway, they would path out the North or East doorways (depending on which was closest), then around the hallways and hit you from the side. Of course, people not aware of this might tag something in the room and back into the hall to fight it, wonder what was taking so long, only to be hit by a massive train coming around the corner in the hallway, having aggroed everything along the way.
You could, in theory, use this to your advantage though. I once made a mob basically run back and forth for several minutes by simply stepping in and out of the room. He'd run towards me, I'd step back. He's run back towards one of the other exits. I'd step back in and he'd turn around. Ok. Not terribly useful unless you'd already cleared the room first, but still something you could play around with if you wanted (and probably far more useful for say a necro using dots than my paladin). What appeared at first to be random and strange, was in fact quite predictable. It had such things because the layout of the building was somewhat circular. There were multiple routes to take, so the devs decided to simplify pathing rules to make sure mobs didn't get stuck in a room, running back and forth constantly changing the route to get to wherever the target was, but never reaching it. So the mob always had one path to get from point A to point B, even if it wasn't always the most physically direct. That path could change if you moved, but never as a result of the mobs own movement (which was the point of the coding).
They've massively improved pathing point granularity in the game since then, so this doesn't tend to happen as often, but back in the day, this sort of odd "run off to the side first, then run towards you" behavior was pretty common, even in outdoor zones. And if you learned that pathing, you could totally take advantage of it and make mobs (or trains of mobs) move in what appeared to be odd and unpredictable directions. I never used this knowledge for evil, of course, but I could see how it easily could be. And for outdoor zones, a bard was certainly the class to use to do things like figure out mob pathing and timing. So it's not unlikely at all that this is how Fansy did what he did.