Walking should prompt a move silently check

[Enderoc]

As the title says but without a hide check. Running should have a negative ten to move silently plus any armor penalties.

[Enderoc]

So an assassin could simply walk or with high enough MS run up behind a target as long as they were not facing him and apply any type of SA or SA enhancement.

Sneaking is trying to stay hidden, but it's absolutely feasible to be light on your feet without trying to stay hidden silently in shadow.

On another note you should not just see a blinking red outline when your listen check reveals an enemy in stealth. There should be an onscreen warning when your skill check acknowledges you hear footsteps within range not just what is in your perspective.