No wind, or rustling or conversations.
I agree with you there's no wind or rustling, but, no conversations? I can't name the number of times I've passed groups of people and overheard conversations between two (usually two, maybe more sometimes, but I haven't noticed it) NPCs. Actually, there seems to be weird glitches with that where you'll trigger one, walk away, have it Doppler fade, then WHAM, next line will be at full volume and will not shut up until the ambient has run through to completion, even if that means overlapping with a quest dialogue cutscene you're doing. :P