Nailed that one.
Nothing undervalued, if I'm stealing the silverware and clothes of rich people, I WANT it to be worth more than an average reward of 50 gold per house.
Increasing levels of guard presence after your crime streak, which will relax after a period of time where no thefts or murders are reported. (With exceptions in areas under TG and DB influence).
A guard staying inside of a recently hit shop or other non-residential facility during the night for week proceeding the hit. And the guard does investigations of the murder of someone. (made little sense to see this in only that one quest in Oblivion).
Ooo, and a disguise system similar to New Vegas, most of the grunts will ignore you, but the officers will see through the disguise. Adds a whole new aspect to sneaking around.
ALSO: I would never want it to be "lol, life sentence or execution" because I was a really bad boy. It might not be as realistic then (but then again, you can shoot fireballs out of your hand at a dragon), but do you really want it to be "fight your way out of a large, sprawling dungeon whilst completely unarmed and unarmored?" I can see the frustration of the less experienced TES players now, you have to fight though the dungeon while making a dozen saves because you're tired of getting owned by all the guards, only to find yourself against the Captain, who tears you apart. Good times.