The sneak cone obviously needs to be tuned to be small enough to make it viable, but more importantly, there needs to be a minimum amount of time that a character is in a view cone for them to appear. Otherwise it doesn't matter how small the cone is, you just turn around in a wide arc and you'll probably find the rogue no matter where they are, even if you're view cone lands on them for a tenth of a second. More points in sneak should grant extra time you can be within view cones before being discovered.
Could be as small as .2 seconds per point in sneak, so enemies would have to look at you for a full second with sneak 5. Would help in single player some too without being too significant of an advantage I think. Would let you run through view cones or avoid being spotted by the guard who does a 180 in half a second. And other players in PVP would have to make a good guess about looking exactly where you are or spend multiple points of AP looking in different spots instead of just scanning to find you. There's still the issue of The Pawn letting you look all over for 0 AP though. Not sure what to do about that. I dunno, maybe The Pawn further reduces the range/width of your vision cone? Kind of to signify that a Pawn only sees what's right in front of it, dunno.
I've actually found that the Sneak cones do grant a little leeway for entering the edge of them (at least with Sneak 1, not sure if it's still the case at Sneak 0). You can sometimes sneak through a narrow area which looks like it is mostly covered by a sight cone without getting spotted.
