Some things to think off with weapon traps:
they can jam when they kill something. Not stuffing them with 10 traps lets you cover more ground while still being plenty deadly. Goblins that bleed to death won't jam a trap, menacing spikes could be a good friend to you. The most horrific efficient 'trap' I used once was a long field of menacing spikes, not in weapon traps but upright spikes, all linked to a lever. I just had to get the dwarfs far enough inside with a civilian alert and set the lever to be pulled on repeat. Spikes don't jam and nothing that attacks you has metal boots or greaves, at least in vanilla. Glass, copper or iron spikes, everything kills. I usually waited untill sufficient numbers got in before I got things going, because too many enemies ran away and escaped. Every four rows of spikes had a row of cage traps for life training purposes. If a squad hung around a cage where a squad leader was captured, the spikes soon finished them or scared them off.
An artifact cabinet was at the end of a short, spike trapped corridor. It attracted building destroyers and because they couldn't destroy it they just stood there forever and ever, or untill the lever got pulled a few times at least.
It was one of the most boring forts I ever had.