I dunno. While it'd be fun to play with, it'd be very difficult for Toady to set up the code to understand who killed who.
I think it's something worth doing eventually, though. A more robust system of assigning blame for events will be necessary when the adventurer skills arc comes out, otherwise adventurers will be able to murder anyone they want using pits and collapses.
What is needed is the ability to assign 'responsibility' for an object or area to a dwarf. So, for instance, let's say I build something. Responsibility for the structure (and its component parts) is assigned to me. If it falls apart on its own and one of its blocks kills someone as it falls, I get blamed, because those blocks have me stored as the responsible party.
When you pull a lever, you take on responsibility for whatever is at the other end, and its component parts. If you hit a building, or throw something, you take on responsibility for it. When you dig or destroy a support, you take on responsibility for the surrounding earth (so cave-ins that happen are considered your fault.)
There would also be some rules for 'chaining' responsibility between objects in various logical ways. For instance, when water or lava passes through a floodgate, anyone who is responsible for that floodgate also becomes responsible for the liquid (so anyone who I drown by opening a floodgate is my fault.)
When you light something on fire, anything that catches on fire from
that becomes your responsibility, in a chain, though if someone else throws a flaming object, they assume responsibility for it (because throwing something makes it your responsibility, of course.)
This may result in some odd cases where the wrong person gets blamed, but I think they would tend to be realistic-feeling cases of misplaced blame -- I throw something at the pillar, it collapses for unrelated reasons, I get blamed. I light something on fire and trick someone into throwing it, they get blamed. Not so weird.
Possibly responsibility could also have an intensity (how likely what you did is to cause immediate responses -- pulling the lever is a more intense response than digging the channel the water flows through) and a durability (pulling the lever two seasons ago doesn't make you eternally responsible for the lake.)
Perhaps someone should have to see you to start assigning responsibility. But you get the idea.