I had asked this for facial expressions in particular, since I found it stupid that I could /harvestdance for days non-stop but couldn't be /annoyed for over 10 seconds. Sadly the devs responded with a pretty flat "no". Still bugs me today...

Regarding the idea to extend this to all emotes, I'd agree only if at the same time we were given an option to filter off noises caused by others' emotes, cause the last thing I'd want is a bunch of players spamming /stretch or other emotes with erotic-sounding moans next to me.