Doesn't that argue *for* giving bows a sneak damage bonus? Otherwise sneak for an archer character becomes a useless skill since they won't detect you no matter what sneak level you have. This at least allows a sneak character to dish out more damage before the enemy closes the gap.
Don't think it is useless, you still have the option to use a melee weapon. Even archers might use a short sword. Imo not every skill needs to be super useful for every type of character. Otherwise mages would have to get a sneak bonus as well for fireballs. In that case it is more important to me that you get no important bonus for free. Since there is absolutely no skill required (neither a high game stat, nor player skill) it is just a free bonus. You could as well just increase overall bow damage by 10%, would be about the same effect.
I also play with mods that make everything deal much more damage, maybe that's why I don't even need it. If I had marksman 100, agility 100, a good bow and some nice arrows I wouldn't need any bonus to kill enemies before they close the gap, at least not a single enemy or even two if I'm fast. If I made 3x bow sneak attack damage I could kill most things with one hit.
But of course all this is a matter of taste.