The one thing I've noticed is even with all the perks in sneak taken I get detected as soon as the arrow hits or misses a target (I'm usually wearing dragonscale light armor). I shoot, the eye opens up, basically no matter what I do or how far away the target is. Would doing enchants that give a bonus to sneaking be worth trying out? I usually just enchant archery and stamina, along with muffle and carry weight increase. Should I also add sneak in there on armor?
I can confirm this. As a ranger, sneak is only useful to get into position. Once first arrow flew, there's no going back to shadow like melee assassins. Your best bet is to dispose of them before they got close enough to whack you (Unless you got a follower / conjured being who can serve as distraction).
??? I don't understand this. I can snipe off whole hordes of enemies and never be seen - and this is before my sneak archer maxxes sneak. There's a couple of things I can think of that may account for this - followers jumping the gun, and the reported over-buffed sneak 'bug'. (The latter is where you fortify sneak over a certain amount, and instead of giving you better sneak, it actually 'rolls over' and you sneak skill drops to low levels instead). Well, there's tactics too.
One thing to remember as a sneak archer is that, when at all possible, as soon as the arrow flies, move back and away. Find cover, move out of it slightly to plink yer target, and quickly get back under cover. Line of sight means a great deal to this game, and so does patience. AAAAAND so does taking advantage of AI and potions - distracting the baddies with a purposeful miss, using poisons (esp. slow and paralyze), and the great let-the-arrow-fly-and-quaff-an-inviso-potion-before-it-hits thing. Sure, there's been quite a few times I've been detected, but that's what sprinting is for! Run away and hide, and when they lose you, start over again. I generally don't worry too much about armor as I never intend on being in melee combat.