I'm sure many players (mainly melee) would tend to agree with me here:
Being in melee in a 25man (even 10man) raid totally overloads you with sounds.
Be be it arrows of hunters wizzing by, arcane missiles from mages or even the constant growling and moaning of the other players around me. While this would all help make a cool sound environment it is HIGHLY overloaded.
Why don't you just CTRL+S you may suggest now. But wait, there's more!
I, for one, immensely enjoy the bosses and all their lovingly recorded dialogue and voice snippets they have. Especially the Sha of Fear has done it to me. His voice acting is awesome.
Unfortunately, I rarely get to hear ANY of it with all the sound overload going on which sucks.
It has driven me as far as to go and "mute" specific abilities one by one by placing (I checked, it's not against ToS as I'm not modifying any game files) empty .ogg/.wav files in my WoW installations Data\Sound\ folder to get some quiet.
This has given me some peace and quiet and I can truly enjoy all the bosses have to say and even understand what they say (Acutally, all sounds but the VERY annoying Rogue Ability Shadow Blade ability which i haven't been able to pinpoint to this very day).
It also allows me to record (Fraps) our first heroic kills in a way where the viewer can hear the bosses as well instead of just my mouthbreathing and the general TS yapping going on ;)
But should I really have to be doing this? Vanilla - WotLK had a Sound at Camera mode. That let me only play sounds that were heard at where my camera was. This was for no known reason removed in Cataclysm.
What I'd really like from the Devs is another Option to let me regulate Boss Emotes/Sounds only. We currently have Master Volume, Music, Ambience and Sound Volume. Just add a Boss Volume there so I can just shut the others down and ONLY hear bosses.
I'd love to hear from other people if they feel the same way or if I'm really just the odd one out of the bunch.
P.s: There's an Addon that plays back Sound emotes based upon the Yell messages but that doesn't always work (especially with new encounters or emotes that are not transmitted via text): BossFilter.