Never used them, but I've just started an archer character and it is bloody hard. More skill though I guess! I tried switching it back on for the archer but I'd got so used to it without that it was just annoying having a thing in the middle of the screen. I've got a lot better at shooting without it though. Definitely more satisfaction when you get that sweet ass long range sneak kill without the crosshair!
I've been able to figure out the spot where it will go on the screen. It's about a centimeter above the point of the arrow. That doesn't make it any easier when something agile and fast is charging at you, though.
Oh, and you lied about the long range sneak kill without the crosshair. When you sneak, the crosshair still pops up because of the hidden icon.