Did a google search, didnt find what i wanted, so i would like to post here.
Basically, i took a 1month break and stopped at 1.5.26
Now with 1.6.89(i think, it is the official 1.6 not beta!), i see/hear dialogs i never seen/hear before in skyrim. I cannot remember details, but some of them were Guard dialogs which comment about combat 'MOVEs'. It may be a mod, since i use SkyRe, but still it is awesome.
Another dialog i see/hear is a random conversation between 2 farmers(i use populated cities).
The third dialog that i can remember is a dialog between Balgruff's children, something about dresses i think.
Anyway, it may be that i simply did not notice these dialogs in 1.5.26, but what about the guard dialogs? I am pretty sure i heard all of them in patch 1.5

Some npcs just glitch and you won't hear their ambient dialog. I also know that they can glitch if certain quest-lines are started, especially the bloody Companions.

I noticed a lot of new ambient dialogue from NPCs after the 1.5 patch (on PC). Don't have 1.6 yet but if it gives me even MORE stuff I haven't heard before, that would be awesome.