I'd also like to see some sort of War glory ethics in place. Something to make certain cultures, like Goblins, have a higher chance to declare war then other races. This would be especially useful in getting Goblins to fight each other, which you'd think would be in character for them.
In addition, I'd like to see all of these ethics be replaced with a system more like personality. Have things be on more of a sliding scale, so that the game can have humans who are ok with slavery, and ones that aren't. Dwarves that are into harsh punishments, and ones that aren't.
For example, Dwarves could have
[ETHIC:KILL_ENTITY_MEMBER:0:5:10]
[ETHIC:KILL_NEUTRAL:0:20:50]
[ETHIC:KILL_ENEMY:100:100:100]
[ETHIC:KILL_ANIMAL:100:100:100]
[ETHIC:KILL_PLANT:100:100:100]
Where 0 is Capital Punishment/Unthinkable and 100 is Acceptable. We could have Human civs who are more like the Elves and respect animals, and ones who are ok with Killing in general. Maybe weird ones where killing enemies is fine, but innocent animals is a major crime. In any case, it'd make things more interesting and allow for much more variety in the world.
It'd also get the humans killing each other more, and maybe even inter-elf or inter-dwarf wars. It'd be nice to differentiate between ENTITY and CIV, so that you can have groups that will gladly kill someone of another nation, but won't try to kill thier own people.