Two more trait ideas:
Spreadfire:
Requires: 1 for Hellrunner, 1 for Finesse
While using chaingun, plasma rifle, or dual pistols, and if the enemy dies while still firing, the remaining bullets are automatically aimed at the nearest enemy. So if you shoot a former human with a chaingun, but it dies after three shots, the remaining two will be directed at its neighbour. This skill is, obviously, cumulative with Happytrigger.
Grenadier:
Requires: 2 for Brute.
Allows to throw rockets without a rocket launcher. They can be thrown over monsters and obstacles (except for walls), so they will always reach their target. The rockets can be thrown 5 spaces away at maximum, but the amount increases by 5 with each subsequent point spent on the trait. This skill can be used on AoB, and the rockets deal 2d4 damage when used on melee.