Originally Posted by
Nathasil
Actually, he did not read it wrong, the tooltip explicitly states that the damage is increased against multiple enemies.
OT:
1) The Trinket does not need a "secondary", it has agility, which is the best passive stat available from a trinket and even as a pure stat-stick COMPLETELY ignoring the procc it is probably still one of your best trinkets, as trinkets are shit overall this expansion.
2) It is important to understand what the trinket actually does. The spawned canon is stationary. So if you continue to move the mobs around (as you usually do in M+) the canon will not hit them.
The procc should be worth 7710 damage (tooltip info @410); which seems to perfectly fit your ~900 avg damage including crits, considering you were probably fighting multiple mobs most of the time it procced. At 2PPM this means the procc is worth 14k DPS.
Also, the canon does damage in a CONE. Which means if the canon is very close to the enemies (as it usually is for melee) the actual area it can hit mobs in is very, very small.
Conclusion: The procc is extremely bad for melee in a RL scenario, it does, however, sim extremely well. Not because it's bugged, but because there is a difference between a sim and a RL situation. You could say Blizzard showed simmig the middle finger designing this trinket.