Wood-elf acute vision is not the same as ranger acute vision as far as I know, unless it was changed. I recall none of my w-elf bards seeing camo/chameleon outside of people in the room with me.

That thief still will have no idea a ranger is in an area or even logged on until it is too late. Sure, they can't be ambushed, but can still be snared and bearcharged into the ground, same as any other thief.

Hell, they won't see assassins hidden in wilderness for the same reason.

W-elf thief actually makes a fair amount of sense to me. I think it is more the hiding in civilized that is contrary to being a wood-elf nature more than anything, not the they see everything aspect.