If you can't settle for 6, make it 5. 5 is the best middleground because it doesn't give too much, but it doesn't give too little, either. This is coming from somebody who's spent tons of time on Bladedancer in D1 and Wraith NS in D2. I think Truesoght needed the nerf; it was too powerful. But there's a line between making something less effective and outright ineffective.