I don't like any of these ideas and I don't think there's a problem. If you don't want to steal, then you, personally, have the choice to not steal. Heck, I have a thief character and I mostly steal from those who I'm already planning to kill (because they're evil). I still have a lot more money than I'm likely to spend. (200,000+ at level 17)
The reason it's broken is there's no lasting consequence for doing so. If the items marked as stolen could not be sold back to any vendor (fences only, as in TES) or if you were unable to wear them in public without being caught by guards or the person that sold them to you; that would be a start.
That would be incredibly obnoxious and tedious having to switch all your gear each time you enter town.
Even if you couldn't sell back to those you stole from (which I don't mind), there are lots of vendors around anyway. There was one particular quest item which is flagged as stolen and forces all guards to search for it when you come near, but I sold it to a random merchant anyway.
Even the most painless addition of a fence for stolen stuff would still be an extra step to take, which adds nothing but annoyance to the game.
I don't just mean they look through your knapsack once and give up, I mean they're constantly on the lookout for stolen goods until you have passed a persuasion check at least once.
Here's the problem with this idea: You do not give civil points very often. You cannot be both good at stealing and good at persuading. So you get screwed over even more, which means even more irritating swapping of stuff on your character. Terrible.
Bribing them shouldn't be as easy as it is now, but correspond to the value of the goods taken and still have to pass a persuasion check (easier than the others). If you fail the check and then commit murder of shopkeepers or Magisters, then a TOUGH party of enforcers shows up with power equivalent to the Flaming Fist or Cowled Wizards in BG2.
Bribing usually doesn't work anyway, not that I've tried it much.
If you fail a check and end up in a fight with merchants you wanted alive, you'll just do what everyone always does and reload.
This isn't an open world game and we don't need an evil bounty hunting party on our asses because someone stole a fork.
In addition to the above, there shouldn't be 100% of a shopkeepers items of every tier showing up in his / her pockets; it should be distributed thus:
No. By the way you can only steal once per character. So already people aren't going to bother stealing until they think they've got as many points into Thievery as they're likely to get. So the lower levels of thievery won't serve a lot of purpose.
In addition to that, there should be a level variance of the gear available to purchase in the shop, within 5 levels of your party, rather than the very latest at all times.
Definitely not. Have you even played this game? That will just break itemization in a frustrating way.
Because of the way scaling on happens, every piece of gear lower than your current level is bad and buying it is a waste. Weapons above your level lose 20% chance to hit per level above, so if you get a bunch of weapons 2-3 levels above your character or 1-2 levels below your character, that's no good. Armor above your level makes you a lot more powerful than you are expected to be.