Sneaking should be much more important and influential, and getting caught stealing should incur a prison time that costs actual XP *and* gold.
This way rich characters risk finishing the game with a lower level, not a bad tradeoff versus best-in-slot gear.
On the other hand, there are tons of ways to become invincible in this game simply because we can load saved games. It's as simple as that. In many ways the player makes the game, if you want to abuse it, you do that, and you will find challenges have dissappeared.
