1. Ermines. Yes I know I already posted a thread about this. That's why I'm not elaborating here.
2. A whale skeleton. Think of it as a level. A whale that has been stripped to the bones is still on the hooks being held up high. You can navigate through the massive skeleton to avoid being seen, or you can sabotage the hooks and cause the massive bone to swing about in all directions, causing massive amounts of damage.
3. Jack the Ripper. Not literally the same person, but a serial killer none the less. A gruesome individual who stalks the streets of Dunwell, and only Corvo can stop.
4. Item crafting. Sort of like Fallout 3. You collect items that can be turned into weapons and equipment. I want to be able to craft bombs, traps, poisons, and even decoys from junk that can be found here and there.
5. Wind up machinery. Wound spring mechanisms were once something of a fad. They were most commonly used in clocks, music boxes and record players, but they were also tested for use in buggies and even elevators. I want to see something really cool.
6. Kieth David. Captain Anderson, the Arbiter, Julius Little, Goliath, Frank Armitage... Need I go on? This guy doesn't get hired enough.
7. Helpful kills. I can understand that not killing guards who are good enough at their job to pose a problem will make life better in Dunwell, but what about rapist, slavers, con artist and other such people? In real life eliminating these people makes the world a slightly better place. I'd like the same thing in Dishonored. If you don't kill a rapist for the sake of not killing him then he just keeps on [censored], but he can't do that if he's face down in his own entrails and thus that problem is averted.
8. New game plus. Pweez?
::EDIT::
9. Home Alone style booby traps that can be built from random crap.
10. Drugs. Like I said in the Merciful Melee thread: I'd like to able to drug guards so they appear to be drunk instead of looking like they've been taken down.