Why does Summon Gargoyle suck?
It doesn’t, but it isn’t very useful when soloing and questing. The gargoyle has a fairly short cast time for its gargoyle strike; the spell hits about as hard as Death Coil, and happens every couple of seconds. It’s terrific for extended DPS in instances and groups since you have a steady influx of runic power and don’t have much down time. While you are questing, half the time is spent killing and the other half is spent running, which makes the gargoyle less useful.