I know Toady wants to find some way to nerf cage traps, and I think a good way to ease into that is to separate their two functions: capturing invaders and capturing local fauna. If individual Dwarves, or groups of Dwarves, could be sent out to capture local animals somehow in a similar way to hunters going out to kill animals, it could balance out the utility of capturing something without making war a riskless endeavor for your Dwarves.
Since at least some additional level of non-lethal fighting is supposedly coming in with taverns, extending that to being able to knock out animals can lead nicely into character carrying mechanics. Animal trappers could be equipped, and if you're not in a savage biome you could just outfit them in leather, and would need to have a net equipped to start sneaking and capturing targets in an assigned zone. Nets could be made from a couple pieces of rope and would be a non-lethal weapon. They'd be useful for thwacking small unarmored things, can be thrown, and have a chance to capture an animal, giving it some status similar to being unconscious on a cage trap. This should be harder for much larger creatures, sort of like having their skulls pummeled, but over time several nets should be able to "knock out" an ogre.
Creatures over a certain size can't be netted at all, so happy fun times and bronze collosi can still ruin your day without things having to be trap-avoid just to avoid being caged. Also, if you want to send out a squad of sneaky Dwarves to ambush the minotaur or try to ambush the goblin ambushers, you could still take a shot at it, it just wouldn't be the guaranteed capture with no Dwarf risk cage traps are.
Plus, finally more weapon material options.