Could you be more specific about the circumstances? I'm asking because one of the characters I run is a vamp. To feed, she has to sneak up on people. Haven't had any issues really.
I have noticed / imagined it on my NB. 1 light, rest medium armor. Trying to move in on mobs of different types to make a hidden attack, it seems to be they easier notice me. May just be me thinking so...
Gotcha. I may not be of much assistance to you then as I've never run a Nightblade. However if it is helpful, it seems that the detection for mobs is such that you have to be square with their buttocks to get a completely hidden icon as opposed to the partial eye, or looking animation.
Dk tank in full heavy and I usually sneak if I am opening up a melee pull. No issues here face to face sneaking. Doesn't work everytime, but when it does.....ooooo man...when it does.