There are too things:
- some NPCs are too strong. This is a settings problem. In another thread, you can see that Xillix did make some changes.
- as I mentioned, evaluation of strength is not correct. A better way will be implemented (might already be in svn, waiting for a new release), but it would still not be perfect for several reasons. You evaluate a person by looking at him. So there will always be things you cannot see. Can you judge someones sword skill just by looking at him when he is sitting below a tree eating an apple? Further, an evaluation should not be on a single figure. Someone having high sword skill is one thing, but if he has a bad quality weapon (which you might or might not see), or you have good armor (which you may know), that does not mean anything.
To be short, some improvements will be done, but it still will not be perfect, and even when it is perfect, it will not prevent you from being killed by someone who APPEARS weaker, or mean that you cannot easily kill someone/thing that seems much stronger.