"Minimal track" means that the fireball homes in on a target slightly. They require care when aiming. I suspect players can dodge them easily unless the he has to stand still. They might be a good counter to someone blocking a door or passageway. A volley of triple-fireballs would be quite deadly to a closely-packed group.
"No damag reduc" refers the damage not being reduced with distance. It hit me for 25 several screens away.