I think the current system with 'LIKES_FIGHTING' tag is a littlebit nonsense in the current form. I mean I'ts kinda disappointing to see giant cave spiders to tear soldiers into shreds, then leaving them on the ground rotting away. It's kinda like wasting precious dwarf meat. It would be cool to see carnivorous creatures consuming the flesh of the killed bodies, leaving a pile of bones and blood splatter on the ground.
Players could use tamed scavengers, to get rid of miasma, and boost up bone production, for example.
It would be another nice feature if the game would generate random eating preferences for forgotten beasts... the eating habit could concentrate for individual organ types. Imagine a horror from the depths crazed for brains, bones, spinal fluid, or hearts, for example. That would be pretty scary, isn't it?
Or even more: inorganic beasts would like to eat objects made out of a specific random material. For example, rock golem would kill your militia, leaving their bodies on the ground and ripping their armour off, to satisfy his hunger for steel, and so on.
I know that Toady will work out the "carnivore" issue, but I was curious how do you imagine how carnivores should work, especially in modding and/or industrial aspects. Feel free to add your ideas too!