Yeah, thinking the same thing: you get an auto-crit if the Draugr doesn't hear or see you, or only hears you but doesn't see you (and they don't see too well). Some of those hits will stun, and if you land a second arrow while they are stunned, it's another crit. You can take a big chunk of hps off before they get close, if not kill them. Keep your eyes peeled and try to see them before they see you. I avoid fighting anything in straight melee (in the higher biomes... I'm always swatting flies in the lower biomes :P). It tends to be things which surprise me or are tough enough that they survive my arrows (one or two stars, or bigger creatures). And yeah it's a good idea to be quiet. Try to avoid fights (though I know the blobs seem to see you from miles away). I really learned to start doing this by the plains stage. Stuff can really hurt there; no sense in attracting unwanted attention.

I think it's actually easier inside the crypts, since it tends to be more controlled. The doorways in the entry room tend to be clogged up, so nothing can get to you to start with. You can mine out a crack in the goop and try to pick off enemies in the next room. This is done mostly at your leisure (though sometimes if the crack is too big and an archer is in the next room, you do need to dodge some arrows coming back at you). But you don't have to worry about some random aggro joining in the fight.

(I've mostly been a mace player btw. I liked the knockback on it. I have hardly done anything with 2handers; didn't want to sacrifice my shield. Maybe they're more useful than I thought.)