I snared him first, then cast Immolate and Swarm of Pain as he approached. As I kited him, I soon learned that he is a summoner. I tried to melee him, but he had the upper hand, even with my healing potions and the fact that I successfully disarmed him. So, I simply kited. When he summoned, I just started kiting all over again, nuking as soon as I recovered them. I didn't melee again until he started to flee.
As for the spell not being much use, well, as one who plans on staying at level 51, collecting AAs until my epic is completed, I'd say it's VERY useful.