Well I'd like idea of better locks I use many mods for Oblivion thats make interaction with doors and locks much more versatile and return many features what was axed from game.
one of mods is
Reneers KeyLock Mod
http://www.tesnexus.com/downloads/file.php?id=33630
This mod allows NPCs to upgrade the locks on their containers and doors after the player has broken into them. If the player steals the key and opens the door / container, the NPC will have a new lock set with a new key.
About robberies I'd like to see such feature as part of quest event for house what we buy, stolen loot better make as stolen gold and misc items thats already was in house like stolen silverware dishes, painting and sconces, I don't think player will happy about stolen loot, so again as part of quest thats really interesting we can pursuit thieves or use deductive investigation found thieves and listen their story what if he was in great need or ask him about invitation into thieves guild, I think thats good idea.
Another good feature if some beggars in inhabitants of slums can pickpocket our character for small amounts of gold if player is not aware about their actions (sneak and security skill checks) to catch their hands, thats can be easy implemented via greeting dialogue,
Or if taverns will be much better we can drink alcohol at drink contest and sleep in tavern or be knocked out during bar fight in such cases we can lose again small portion of gold
If we will able sleep everywhere like in this mod,
Roughing It
http://www.tesnexus.com/downloads/file.php?id=24441
In such cases resting in such manner in public place can also cost us small amount of pick-pocketed gold.
Few ideas about fixing exploits on locking unlocking and lockpicking
If player lock door with key door no more train his security skill and become marked as player owned or already picked, bashed locks are broken and if player is not owner but there is another owner they will be restored at next time but replace by higher grade lock and/or trapped, doors without owner will never restore self so once opened they will not close anymore.
NPC able to unlock doors by key, lockpick, unlock spell or bash lock
Lock spell work in different way it creates magical barrier around door and enchant it for certain duration if barrier was placed by player it can have duration based on skill in alteration school, barrier is physical and magical field around door thats glow and increase door durability versus bash, prevent lockpicking (unless you have skeleton key), but can be dispelled or wear of after certain time or or after take maximum damage from spells and bashes barrier health is based on charged Magicka into it but never have smaller value then 50 for example so there is no barriers with 1HP, when barrier is broken but not dispelled it create noise and flash of light effectively work versus sneaker around and alert NPC nearby, if barrier was dispelled or wear of by self noise is not produced and barriers just blinks and disappear, NPC mages can use such barriers for protecting self from pursuits or protect vaults and treasury as additional security for durable doors with difficult locks and traps, as well such Lock spell can be used as trap to close doors if thieves was unsuccessful to disable trap and activate it, such spell much better then closing door by script like it was before.
Lock spell not physical replace of key to lock door it more like magical force field around door door under such field can be already open or bashed, so it cannot be used to constant locking doors and lockpicking them.
Such spell can also be component for circle of protection spell what already introduced, just use on target function to determine how it work, as well such force field can be used as trap rune what envelope target and prevent it from moving but not harm it and even protect it from damage since it work as force field around them.