Well first off, If somone was behind you you shouldnt be able to see them... like in rl so that us theives can acutally pull off a backstab also begin abelt o scale walls would be nice.
lol the ability to pull cloaks over ones head,

Also in some games you are warned when someon has robbed you this shouldnt be. heh and like in some games Guards insta appear and insta kill you for stealing. Guards should be placed around the town but are not invincivble and should be able to kill or run away from... well thats all i can fink of for now. Oh and when you walk you should be able to hear footsteps unless someone is Sneaking along